The noun has 4 meanings:
Meaning #1:
the act of putting something in working order again
Synonyms: repair, fix, fixture, mending, reparation
Meaning #2:
restraint that attaches to something or holds something in place
Synonyms: fastener, fastening, holdfast
Meaning #3:
the sterilization of an animal
Synonyms: neutering, altering
Meaning #4:
(histology) the preservation and hardening of a tissue sample to retain as nearly as possible the same relations they had in the living body
Synonym: fixation
