pi 1 
(pī)
(pī)n.
1. (also pē) The 16th letter of the Greek alphabet. See Table at alphabet.
2. Mathematics A transcendental number, approximately 3.14159, represented by the symbol π, that expresses the ratio of the circumference to the diameter of a circle and appears as a constant in many mathematical expressions.
[Late Greek pī, from Greek pei, of Phoenician origin; see p in the Appendix of Semitic roots.]
- Indo-European root: (s)mer-
- Indo-European root: sneigwh-
- Indo-European root: (s)neəu-
- Indo-European root: snā-
- Indo-European root: (s)nāu-
- Indo-European root: (s)nē-
- Indo-European root: so-
- Indo-European root: sol-
- Indo-European root: spek-
- Indo-European root: (s)pen-
- Indo-European root: spend-
- Indo-European root: sper-
- Indo-European root: sperə-
- Indo-European root: spē-
- Indo-European root: sreu-
- Indo-European root: (s)teg-
- Indo-European root: stegh-
- Indo-European root: steig-
- Indo-European root: steigh-
- Indo-European root: stel-
- Indo-European root: (s)tenə-
- Indo-European root: ster-
- Indo-European root: ster-
- Indo-European root: ster-
- Indo-European root: streb(h)-