the bottom or lower surface
WordReference Random House Learner's Dictionary of American English © 2025
WordReference Random House Unabridged Dictionary of American English © 2025
un•der•side
(un′dər sīd′),USA pronunciation n.
- an under or lower side.
- under- + side1 1670–80
Collins Concise English Dictionary © HarperCollins Publishers::
'on the underside of' also found in these entries (note: many are not synonyms or translations):
agaric
- agaricaceous
- air dam
- black widow
- boletus
- chain stitch
- cicada
- clamshell door
- comma
- fern
- frenum
- gill
- iceblink
- misericord
- pad
- question mark
- redlegged grasshopper
- rib
- snowblink
- soft tick
- sooty blotch
- sublingual
- tooth fungus
- tube