In biology terms the difference between spermatid and spermatoid
is that spermatid is a haploid cell, produced by meiosis of a spermatocyte, that develops into a spermatozoon while spermatoid is resembling sperm or semen.
As a noun spermatid
is a haploid cell, produced by meiosis of a spermatocyte, that develops into a spermatozoon.
As an adjective spermatoid is
resembling sperm or semen.