When looking to pick a horse to back in racing, what does 0 or - or p stand for when looking at the form?

Question

When looking to pick a horse to back in racing, what does 0 or - or p stand for when looking at the form?

Answer 1

p= pulled up

0= finish in 10th position or worse

Answer 2

I think 0 means not placed and p could mean placed, but not in top 3. Not 100% sure though.

Answer 3

o means outside the first 10. if you see a horse with form 0000000100000001 back it as it means the trainer and owner are having a gamble with it.

P means pulled up

Answer 4

O= unplaced

P = pulled up.