It is vertex which is the singular of vertices's.
A cuboid douses have 8 verticess and 12 edges.
Square pyramid: 5 Cube: 6
Bacterium is the singular word.
the singular word it is salmon.
singular
Adenoma is the singular of adenomata.
The word 'Phenomenon' is singular. The plural form is 'Phenomena'.
singular of the word stitches is stitch.
Lance is singular.
The word "hang" is singular.
The word dog is the singular form.
Yes, the word "document" is singular.