say it: dahy-LAY-shuhn
dilation is a noun meaning "a lengthy discussion (spoken or written) on a particular topic". It carries 2 recorded senses.
a lengthy discussion (spoken or written) on a particular topic
the act of expanding an aperture
“the dilation of the pupil of the eye”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for dilation come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.