LP measurement

• Tach reading, for short
• 45 or 78, for short
• 78 letters
• 45, notably
• 33 1/3, e.g., for a record: Abbr.
• "Tach measure, for short"
• Turning speed: Abbr
• 33 1/3, e.g

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1906, initialism (acronym) from revolutions per minute .

Wiktionary Word definitions in Wiktionary
n. (alternative capitalization of RPM English) n. (alternative capitalization of RPM English)