>i think i am with wordwind on plumb.. crazy...

you guys is plumbful of good notions. the word plumb (often spelt plum), while originally meaning vertical, perpendicular or straight down (rarely straight up), through transferral (hi bill!) has come to mean exactly, directly or precisely (and in US slang becomes an intensive: completely, entirely, absolutely, quite).

[and speaking of plumb lines, contrast them with rhumb lines -- or loxodromic curves.]