Percival is often explained as "pierce the valley," though that reading may be a later poetic gloss rather than the name's true root, which remains genuinely unclear. What has stuck regardless is its association with a knight defined by a long, uncertain search -- a name tied to quest more than arrival.
The first sign hath pre-eminence in signification, when there be two signs have to do with the thing. - William Lilly (1602.-1681.)