beta
n.— «There are also a bunch of people there who do not climb real rock. i was talking with one guy and we were disucssing the beta on a 5.11a. i asked him about what kind of stuff he was leading and he said, “leading? like outdoors? oh, i’ve never done that.”» —“Re: Best use of ugh climbing wall” by Bob Pasker Usenet: rec.climbing Apr. 13, 1991. (source: Double-Tongued Dictionary)