There is a manual that was created by knowledgeable fans of the game (PDF file in the game folder), but don't believe it provides abbreviation information but I could be wrong so feel free to check. Took me a bit to find where you were seeing those items, appears its on the recruitment screen. If you do double click on the player, you can "kind of" figure out what each means. Also, highly recommend any future questions about College Basketball 2018 be posted in the official forum where other people are likely going to see it, plus you can even browse the forum for other possible information that may be helpful although it might not be that active since 2018 is two versions old.
Forumviewforum.php?f=272In your case, the items mean the following:
OV = Overall ranking of the player nationally
PS = Position ranking of the player nationally
On other screens like roster statistics, there is a help key within the game that shows you the abbreviations.
For player ratings, you can double click on the player and you'll see player card with full rating names.