(idiomatic) Only love, sole sweetheart.

(travel, UK, Ireland, dated) A package holiday rate without confirmed accommodation reservations, or using a dummy reservation, enabling the tour operator to sell charter airline seats in competition with the airlines.

(before adjective) very, all too. / (before adverb) to a high degree; very well or very much

(chess) The only move to maintain the current evaluation of the position. / Used other than figuratively or idiomatically: see only, move.

A person who has no siblings. / A person raised as the sole child in a household.

plural of only child

recently; just now / barely; by only a small margin

(rail transport) Describing a railway line that is used only by freight trains

Being the only child of one’s parent (especially one’s father) / (Christian theology) One of the attributes of Jesus Christ, the only-begotten Son of God the Father.

(computing) Unalterable, capable of being read but not written.