The word “quick”
The ordinals (i.e. first, second, third, fourth, and fifth) refer to the ordinal positions of the letters of the answer word “quick” (i.e. “q”, “u”, “i”, “c”, and “k” respectively). These letters have the same sound as the words described by each clue, as follows:
Line 1: first letter – q/queue – A “group” of people may form a queue (lineup) “to get inside” somewhere (e.g. a store).
Line 2: second letter – u/ewe – A ewe (female sheep) “is prized for” its wool.
Line 3: third letter – i/eye – An eye “does reside” “in the skull”.
Line 4: fourth letter – c/sea – The sea “goes up and down with the tide”.
Line 5: fifth letter – k/cay – A cay is an island, and therefore “has water on every side”.