cyst
UK[sɪst]US[sɪst]
n
A sac in the body, containing fluid or soft matter, that develops abnormally.
n
A protective capsule or spore case in some plants and animals.
Etymology
The word 'cyst' entered English in the early 18th century via modern Latin 'cystis', which was borrowed directly from the Greek 'kystis', signifying a bladder or pouch. This Greek term is believed to derive from the Proto-Indo-European root keu-, meaning 'to swell' or 'to be vaulted', a root that also gave rise to words like 'cave' and 'cumulus'. The medical and biological application of 'cyst' to describe an abnormal membranous sac or a natural protective capsule perfectly preserves the original Greek concept of a contained, pouch-like structure. Its journey from an ancient term for a common container to a precise scientific descriptor illustrates the direct borrowing and semantic specialization of classical vocabulary.
Analysis
The entire word 'cyst' functions as a simplex morpheme. It originates from the Greek 'kystis', meaning 'bladder, pouch'.
Examples
The ultrasound revealed a small, benign cyst on her ovary.
After the infection, a painful cyst formed under his skin.
Some aquatic invertebrates form resistant cysts to survive harsh conditions.