Alphabetical order is an method of sorting in which objects are arranged according to the order that the letters of their name (or another important characteristic) appear in an alphabet. For example, using a standard English alphabet, the letter C appears before the letter L. Thus, on a list in alphabetical order, "caramel" would come before "lime". If the initial letters are identical, subsequent letters are compared in the same manner. ("Baker" comes before "Ball".) If there are two words so that one word consists of the other plus X other characters, the shorter word will be listed first. Thus, "ant" comes before "anteater" or "antifascism".

The upside of using this order is that it is extremely easy to search. Given the word an entry would be filed under, it is usually possible to determine the general region it would be filed in, and from there it is usually fairly simple to further narrow your search - looking at any entry will allow you to determine if the object of your search would precede or follow it. For this reason, dictionaries, telephone books, and encyclopedias are all presented in alphabetical order, and many filing systems, directories, and more obscure collections of data use this system as well.

A downside of filing things by alphabetical order, however, is that the order is rarely particularly logical as it pertains to the items themselves - entries relating to each other may be distant from each other, while consecutive entries may have no conceptual overlap. "Wedding" is more closely related to "marriage" then to "wedge", but you wouldn't know it from the order it appears in a dictionary. For this reason, many classification systems organize things into broad categories by alphabetical order, with relevant entries sorted under these headings - for example, a lawyer might sort his files alphabetically by client name, with all correspondence or files dealing with that client filed in chronological order under the client's name. (It is, of course, entirely possible to do this subsorting by alphabetical order, as well – for example, the Yellow Pages lists types of businesses alphabetically, listing individual businesses alphabetically within each type.) This is also the reason that names are usually sorted by family name first, and then personal name (and then middle, baptismal, or any other names), even in western societies where names are customarily presented in the reverse order. This way relatives, who share family names but not personal names, will be grouped together.