It starts like this: You’re staying at a friend’s or relative’s place in another town or state. You decide to cook a fabulous dinner for them and head out to the market.

In the produce section, you scan the offerings, and just when you think you have found what you need, you look at the sign and it is labeled something else. You stand there, confused and feeling too foolish to ask the grocer “What is this?” when it seems as plain as day what it is.

What’s going on here? What is your English-language cookbook referring to when it calls for courgettes? Why was that arugula you found in the market while visiting your grandma down South marked rocket?

The culinary world has many idiosyncrasies. But the answer is quite simple. Foods go by different names from country to country, region to region, even town to town. So, what I call scallions, someone in California might call green onions, and someone in Minnesota might call spring onions. What I call hearts of palm would most likely be called palmitos in a Latin American market, and what is cassava or yucca in a Latin American market might be manioc or tapioca root in an Asian market. Confusing, right?

The Cook’s Thesaurus [www.foodsubs.com] comes to the rescue with an amazing collection of synonyms and pronunciations for just about every type of food you can think of.

The site is divided into categories, subcategories, and so on. The main categories are Vegetables; Fruits; Dairy; Flavorings; Liquids; Grains; Grain Products; Baked Goods; Legumes & Nuts; Meats; Fish; Vegetarian; Baking Supplies; Fats & Oils; Accompaniments; Equipment; and Miscellaneous.

Each item within these categories is accompanied by a brief description or method of use. How many times have you seen an ingredient at the market and thought, “What is this used for?” The answer may very well be here. Been wondering lately what kewra water is for? Cook’s Thesaurus says that this “is an extract that’s distilled from pandanus flowers and used to flavor meats, drinks, and desserts in India and Southeast Asia.” (Won’t you sleep easier now that you know that?)

Most items have photos as well. This is helpful when you are trying out a new—possibly exotic—recipe and are not sure what an ingredient looks like. I never would have known what a rambuten, for example, looks like until I saw a picture of it on Cook’s Thesaurus (it is similar to litchis but with spines all over it). Nor was I aware that turmeric root looks almost exactly like ginger root. And I finally know what those long bean-pod-like things in the Latin section of my supermarket are—guajes! Knowing what an unfamiliar item looks like is especially important because of the first point I made in this article: Things go by different names, depending on where you are.

The Vegetable category covers all types of vegetables, including roots, tubers, stalks, leafy greens, and sea vegetables (various forms of seaweed). Cross-referenced here and in Fruit are the “fruit vegetables"—that is, tomatoes, eggplants, squashes, cucumbers, peppers and chiles, olives, avocados, and tomatillos. Also under Fruit are exotic tropical fruits, which may just introduce you to a whole new world of produce, from ababai to zapote. It is appropriate, even if you may not have thought of it, that preserves, fruit butters, and candied fruit appear here as well.

For those looking for dairy alternatives, there are many in Non-Dairy Milks & Creams in the Dairy category. Cheeses are listed under seven subcategories (such as Fresh and Semi-firm). Under Eggs, you will find lots of egg substitutes for baking and binding. Different species of eggs are also shown, such as quail and salted duck eggs, with their uses and substitutes.

The Flavorings category is pleasingly diverse. It does not just stick to spices and extracts. It runs the gamut, from extracts and essences to sweeteners, international condiments, vinegars (did you know about coconut vinegar?), and alcoholic products. The last two are cross-referenced under Liquids, along with other obvious entries.

I am a grain lover, so I particularly like the Grain category, where you can get information on not only different types of grains but also their various incarnations (such as wheat flakes and pressed barley). Rice (which I particularly love) is a very diverse product, and here you might discover a few rice types you have never seen before. Now, I am a food writer and I cook and experiment a lot, so I have seen (or at least heard of) a lot of different rices. But even I made a new rice discovery here—pinipig, or glutinous rice flakes, which according to Cook’s Thesaurus, “Filipino cooks use…to make desserts and drinks.”

For those with wheat sensitivities, peek in on the Grain Products category under Non-Wheat Flours and Nut Flours & Meals for a host of wheat flour substitutes. While I would not rely on Cook’s Thesaurus for a comprehensive list of different Italian pasta shapes (as there are hundreds), it makes a good dent in them, showing most of your commonly found types and more. Impressively, it also shows different kinds of pasta. For instance, people with wheat allergies would be very pleased to find out that corn, quinoa, Kamut, and spelt pastas can be found. On the other hand, it does a great job of describing Asian noodles, separating them by both grain type and ethnicity.

The Vegetarian section pulls together products from the other categories that are inherently vegetarian (not including fresh vegetables and fruit—those speak for themselves). Particularly helpful to vegetarians is the Soy Products section.

Especially helpful in the Accompaniments category are Olives and Mushrooms, since many types of both of these look so similar. Both text and photos help identify them. Also edifying are Candied Foods and Edible Flowers. Not botanically inclined myself, I find the photos a useful guide to distinguishing edible flowers.

The Equipment category is a little lacking in information (you can get a better list from Web sites like Cooking.com, Fantes.com, or Epicurious.com). The list is neatly divided into useful subcategories, like Extracting & Straining Tools and Mashers, Graters, Mixers & Grinders, but when you click on them, the entries are paltry. It also has a few strange quirks, such as the fact that in Measuring Tools it lists thermometers (which, of course, measure temperatures), where one is expecting to see measuring cups and spoons, scales, and other such implements. Under Outdoor Cooking Equipment you will find only one item—bamboo skewers! What about barbecue grills, planks, or campfire equipment? And there is only one item under Cleaning Tools—a mushroom brush. Perhaps the Webmaster intends to continue the lists.

One category that is both unexpected and strangely thorough is Miscellaneous. In here are such subcategories as Caviar & Roe, Food Wrappers, and Thickeners. When I clicked into Food Wrappers, I expected to see won ton wrappers. Well, yes, there are won ton wrappers, but they also show aluminum and plastic wrap, leaves—bamboo, banana, fig, grape, lotus, maguey, papaya, and ti—not to mention corn husks, sausage casings, and a variety of ethnic “skins” (i.e., empananda wrappers, egg roll wrappers, gyoza wrappers, etc.). And would you ever think to use sago starch or water chestnut powder as a thickener for your soup?

One of the most useful features of Cook’s Thesaurus is the substitutions. I have often encountered recipes—particularly for dishes native to other countries—that call for ingredients that are difficult (if not impossible) to find here in the U.S. While the Internet is a great resource for anything you might need, the drawback is that you have to wait for delivery, which means you must plan ahead. But suppose you need something spur of the moment—what do you do? Substitute, the mantra of harried cooks.

Cook’s Thesaurus lists substitutes that you may never have known existed for many items. If you have a recipe that calls for candlenuts (popular in Southeast Asian dishes), Cook’s Thesaurus will tell you that you can substitute hazelnuts (when was the last time you saw a candlenut?). Have some sour cream on hand? Use it as a substitute for smetana (an Eastern European sour cream) or jocoque (“a Mexican product that’s halfway between buttermilk and sour cream”).

Sometimes substituting means making your own version of commonly found products. For example, to make buttermilk, combine 2 cup of milk (or soymilk) plus 2 tablespoon of lemon juice or vinegar, and allow to stand for 10 minutes; or, combine 1 cup of milk plus 2 teaspoons cream of tartar, and allow to stand for 10 minutes; or, combine two parts plain yogurt plus one part milk or plain, low-fat yogurt or sour cream or molasses (in batters that also call for baking soda).

Each month the site features an ingredient of the month, which appears on the home page (although it is not necessarily updated every single month). At this writing, the ingredient was chocolate. It explains its origins and gives information on how to work with chocolate and store it. This feature could stand to be expanded a bit, giving more information than it does and incorporating more concrete instructions on usage as well as a little history. But perhaps that would truly be reaching beyond the scope of the site.

Cook’s Thesaurus has won numerous awards and honorable mentions. Access Magazine, for example, named it one of 2000’s Best Sites of the Year. It also was mentioned in The Complete Idiot’s Guide to Online Health and Fitness. It was honored by such sites as Yahoo! and Food & Wine Online as a Site of the Day, and it was positively reviewed in The New York Times and The Washington Post. Click on Awards at the bottom of the home page to read the excerpts.

Even if you don’t cook much, or are shy about trying new foods, Cook’s Thesaurus is a fascinating site to visit. You will walk away with an expanded knowledge of foods from around the world. Wouldn’t it be great to know your kombu from your wakame and your epazote from your huauzontle?

Roberta Roberti is a Brooklyn-based food writer who owns her own chef business and has written a soon-to-be-published cookbook on vegetarian Italian food.