ˈmīkrə+ˌ- noun
Etymology: International Scientific Vocabulary micr- + cyst
1.
a. : a small cyst or spore (as a chlamydospore or a resting cell formed from a slime-mold swarm spore) — compare macrocyst
b. : a minute resistant body in some higher bacteria that is thought to be a haploid spore
2. : a very small pathological cyst ; especially : one arising from another cyst