9 across
Like
0,
nothing
(0)
divides
51500
(5)
Like 0, nothing (0) divides 51500 (5)
hints
0
checks
0
hints
The definition is at the beginning of the clue.
How the clue works
The definition is Like 0 — egg-shaped, like the digit zero. For the wordplay, read 51500 as Roman numerals: 0 is O, 5 is V, 1 is I, 500 is D, giving you OVID. Then nothing (0) — another O — is told to divide it, slipping inside between the V and ID to produce OVOID.