Meaning

• A question, an inquiry (US), an enquiry (UK).

  "The teacher answered the student’s query concerning biosynthesis."

• A question mark.

• A set of instructions passed to a database.

  "The database admin switched on query logging for debugging purposes."

Meaning

• To ask a question.

• To ask, inquire.

• To question or call into doubt.

• To pass a set of instructions to a database to retrieve information from it.

• To send a private message to (a user on IRC).

• To send out a query letter.