sex gland vs bollock

sex gland and bollock both are nouns.

Word	Noun	Adjective	Verb	Adverb
sex gland	Yes	No	No	No
bollock	Yes	No	No	No

As nouns, bollock is a hyponym of sex gland; that is, bollock is a word with a more specific, narrower meaning than sex gland:

sex gland: a gland in which gametes (sex cells) are produced
bollock: one of the two male reproductive glands that produce spermatozoa and secrete androgens

Other hyponyms of sex gland include ovary, ovotestis, ball, ballock, egg, nut, orchis, testicle, testis.

sex gland (noun)	bollock (noun)
a gland in which gametes (sex cells) are produced	a pulley-block at the head of a topmast
	one of the two male reproductive glands that produce spermatozoa and secrete androgens