IPA: //prəʊˈθɒnəˌtɛri//
KK: /proʊˈθoʊnəˌtɛri/
A prothonotary is a chief clerk or record keeper in a court of law, often responsible for maintaining official documents and records.
The prothonotary filed the court documents in the official records.
Protonotary is formed from "proto-" (meaning first) and "notarius" (meaning notary or scribe). The term originally referred to the chief notary or the first among notaries, indicating a position of primary importance in legal or administrative matters.
Think of 'first' ('proto-') and 'notary' as someone who records important documents — a protonotary is the chief scribe or the first among them.
No commonly confused words.