say it: FIL-uh-muhnt
filament is a noun meaning "a very slender natural or synthetic fiber". It carries 4 recorded senses.
the stalk of a stamen
a thin wire (usually tungsten) that is heated white hot by the passage of an electric current
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 filament 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.