How to pronounce Poisson

Poisson is most commonly pronounced "PWAH sawn" (/ˈpwɑsɒn/). This is the widely-used reading among engineers, though edge cases exist.

The 'oi' is French /wa/, so the first syllable is PWAH, not POY: PWAH-sawn. Named after French mathematician Siméon Denis Poisson. Wiktionary gives General American /ˈpwɑ.sɒn/ (no vowel-length mark) and RP /ˈpwɑː.sɒn/ ~ /ˈpwɑː.sɒ̃/ (the ː length and nasalized ending are RP, not GA). The dominant developer/student error is the fully anglicized POY-sun rhyming with 'poison', which is why the term reliably trips people in stats, queueing theory, and event-rate modeling. Educated stats usage converges on PWAH-sawn, so consensus rather than truly contested.

Alternate readings you might hear:

• "pwah SOHN (nasal)" /pwɑːˈsɔ̃/

Source: Wiktionary — Poisson (English IPA)

Pronouncing project and product names correctly avoids the small but persistent friction of being gently corrected during standups, conference Q&As, and team calls. Hearing the word a few times locks in the right reading better than reading IPA ever will. Pronounce is a community-maintained dictionary — every entry tagged with a confidence level and (where possible) a citable source.