GaryUK

I require some guidance on the correct terminology for the following: In a series of numbers... first / last members - ordinal / terminal (or other)? next / previous members - ordinal / adjacent (or other)? So far I have referred to them all as ordinal (as in 1st, 2nd, 3rd, ..., last), but I want to distinguish between first/last/next/previous. I only ask because I wish to properly name methods in some program code I'm developing. I am not a mathematician or statistician, etc, just a novice. Thanks for any help.