Word: groundsill
Part of speech: Noun
Syllables: ground
sill
Definition: The lowest beam of a door-frame; the threshold.
Morphemes:
Affix: ground
Language: en
PoS: Noun
Meaning: One of the pieces of wood, flush with the plastering, to which mouldings etc. are attached.
Affix: sill
Language: en
PoS: Noun
Meaning: threshold; horizontal structural member of a building near ground level on a foundation or pilings, or lying on the ground, and bearing the upright portion of a frame. Wikipedia:Sill Plate