You can search the OED with either a Quick Search or an Advanced Search.
Things to note:
The quick search finds main dictionary entries, such as cat, break, or xylophone. It also finds phrases and compounds listed within main entries, such as to look up or alphabet book, and variant spellings such as dictionarie.
An Advanced search is a full search of the entire dictionary text. It finds your term wherever it occurs in the dictionary. This could be in the form of an entry name, part of another word’s definition, in a quotation, etc. An Advanced search also allows you to search for words that occur near one another, such as bread before butter.
Some other features are:
As you can see from this example, many of the general keyword results have the word in its quotes. You can narrow using the filters on the right (Subject [food]; Language of Origin [French]; Region [Australia]; Usage [slang]; Date of entry [1800-2000]; Part of speech [noun]; or First Cited in).
You can choose to search items other than keywords. They are:
As with all database searches, use AND, OR, or NOT to search more than one term or to limit a search.
A wildcard is a symbol which stands for any character. Wildcards are useful if you do not know how to spell a word, if you are not sure in what form the term you want appears in the dictionary, or if you want to find several terms beginning with the same root.
Two wildcards are available.
A search with a wildcard retrieves all results which contain matching terms. For example: