Type in the abbreviation in upper or lower case and press Enter or click the Find button. Abbreviations may contain a space or other characters (but only if that's the way they are written).
Do not put periods after letters in the abbreviation or search string (e.g., U.S.A, instead use USA) unless the abbreviation actually contains a period (like X.500). Don't use single or double quotes (' or ") around or in the abbreviation (they will be ignored).
Also, the following characters cannot be part of search string: @, #, $, %, ^, and ?
Watch out for plurals. For example, you might want to know what the abbreviation "pixels" means. Search for "pixel", not "pixels" (without the quotes, of course).
If the abbreviation you're searching for isn't found, be sure you are spelling it correctly. If you're searching for a word or phrase, see Word in Meaning
Word in Meaning search
You can search for words or concepts by using the word in meaning (reverse lookup) option then typing in a phrase or list of words. This will return a list of abbreviations containing the phrase or words you enter.
Searching for a word or string within the meaning of the abbreviation can help you find an abbreviation if you don't know what it is. For example, you could find all abbreviations containing (and thus probably having to do with) "education" or "technology" or "protocol".
Select the word in meaning option and then type in a word to search for. For example, if you type in "restrict" you'll get abbreviations containing "restrict". If you're looking for "restricted", you should use that search string.
To search for multiple words or concepts, type in each word separated by a space. This does a Boolean AND search for all the words you type in. So, if you typed in security system your search would return all abbreviations where both these words were found in the meaning (in any order). Do not use AND or OR with the keywords.
To find an exact phrase, put the phrase in quotes ("). To search for all abbreviations containing the exact phrase "security system", you would type in "security system" This would return abbreviations with meanings containing this exact phrase.
As with short abbreviations, searching for words frequently found in the meanings of abbreviations can generate very large lists. For example, the word "system" appears in over 25,000 definitions, generating an enormous (and almost useless) result list.
Rank is our measure of the relative "commonness", "popularity" or "relevance" of the meaning of an abbreviation. You'll see that the results are sorted by decreasing rank, which means the most commonly used meanings will be listed first. You can re-sort the list with an alphabetical sort if you like and you'll still be able to see each meaning's rank. Rank is available in normal abbreviation searches, and "word in meaning" (reverse lookup) searches.