A phrase.

You can specify that the search results contain a specific phrase.

Topics that contain the literal phrase "cat food" and all its grammatical variations.

Without the quotation marks, the query is equivalent to specifying an OR operator, which finds topics with one of the individual words instead of the phrase.

Two or more words in the same topic

AND and

+ (plus symbol)

& (ampersand)

cat AND dog

"cat food"+milk

"cat food"&"dog food"

OR or

| (pipe)

cat OR dog

cat | dog

NOT not

! (exclamation point)

NOT cat

! dog

cat + (dog | mouse)

cat | dog + (! mouse)