Ability score

From NWNWiki

An ability score is the numeric rating of one of the six character abilities. Some creatures lack certain ability scores; others cannot be rated in particular abilities.

This score can range from 0 up to 255, with an "average" person having a score of 10 (ie no ability modifier). However, legal player characters can achieve a maximum of 57 modified ability score overall, but the highest legal score may vary depending on which ability it is.