[proh-thal-ee-uh m]

noun, plural pro·thal·li·a [proh-thal-ee-uh] /proʊˈθæl i ə/.

Botany. the gametophyte of ferns and related plants.
the analogous rudimentary gametophyte of seed-bearing plants.

Origin of prothallium

1855–60; < New Latin < Greek pro- pro-2 + thallíon, diminutive of thallós young shoot; see -ium
Related formspro·thal·li·al, pro·thal·lic, pro·thal·line [proh-thal-een, -ahyn] /proʊˈθæl in, -aɪn/, adjectivepro·thal·loid, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for prothallium

Historical Examples of prothallium