What means number 5 in name "p5"?

[geraldar]

Library name: p5.js
"p" means processing.
@lmccart what means number "5", why not 6, 7 or other?

[lmccart]

the original domain of processing was proce55ing.net, so people used to sometimes refer to processing as proce55ing or P5 or p5 for short. they still do sometimes. p5.js is a reference to that.