~ 1 [ pʌɪ ]
■ noun
1》 the sixteenth letter of the Greek alphabet ( Π , π ), transliterated as ‘p’.
2》 the numerical value of the ratio of the circumference of a circle to its diameter (approximately 3.14159).
3》 [as modifier ] Chemistry & Physics (of an electron or orbital) with one unit of angular momentum about an internuclear axis.
■ symbol ( Π ) mathematical product.
Origin
from Gk: the numerical use comes from the initial letter of Gk periphereia 'circumference'.
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~ 2 [ pʌɪ ]
■ adjective Brit. informal short for ~ous .