Definition of pipe tree in US English:

pipe tree

noun

  • The common lilac, Syringa vulgaris. Also "blue pipe-tree". Now chiefly historical.

Origin

Early 17th century; earliest use found in John Parkinson (1566/7–1650), apothecary and herbalist. From pipe + tree. First used in the 17th cent. to translate post-classical Latin Syringa in its then wide sense.

Pronunciation

pipe tree

/ˈpʌɪp triː/