a person who contributes to the fulfillment of a need or furtherance of an effort or purpose; "my invaluable assistant"; "they hired additional help to finish the work"
someone who assists a priest or minister in a liturgical service; a cleric ordained in the highest of the minor orders in the Roman Catholic Church but not in the Anglican Church or the Eastern Orthodox Churches
children take the roles of physician or patient or nurse and pretend they are at the physician's office; "the children explored each other's bodies by playing the game of doctor"
a licensed medical practitioner; "I felt so bad I went to see my doctor"
a person who holds Ph.D. degree (or the equivalent) from an academic institution; "she is a doctor of philosophy in physics"
the act of assuming or maintaining a seated position; "he read the mystery at one sitting"
(photography) the act of assuming a certain position (as for a photograph or portrait); "he wanted his portrait painted but couldn't spare time for the sitting"
a session as of a legislature or court
not moving and therefore easy to attack; "a sitting target"