The Collaborative International Dictionary of English v.0.48:
Petiole \Pet"i*ole\ (p[e^]t"[i^]*[=o]l), n. [F. p['e]tiole, fr. L. petiolus a little foot, a fruit stalk; cf. pes, pedis, a foot.] 1. (Bot.) A leafstalk; the footstalk of a leaf, connecting the blade with the stem. See Illust. of Leaf. [1913 Webster] 2. (Zool.) A stalk or peduncle. [1913 Webster]WordNet (r) 3.0 (2006):
petiole n 1: the slender stem that supports the blade of a leaf [syn: petiole, leafstalk]