i Register
In some senses, pi is marked as dated, US, historical. Watch for register when choosing this word.
ADJ.
celebrated, constant, equal, equal, irrational, many, mathematical, moral
VERB + PI
back, buy, computing, like, sipping, teach, value
PI + NOUN
-, ata, characters, colada, county, day, decimal, framework
PREP.
in
ADV.
approximately, rather