As adjectives the difference between overlying and topmost
is that overlying is lying over or upon something else while topmost is at or nearest to the top; uppermost; being the very highest.
overlying
English
Adjective
(head)
lying over or upon something else
topmost
English
Adjective
(-)
at or nearest to the top; uppermost; being the very highest.
Antonyms
* bottommost
See also
* leftmost, rightmost