Simple past tense and past participle of rosin.(verb)
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Use "rosined" in a sentence
"I would have it done where the forend could be taken off by hand, but you would need rosined blocks and a little force to break it loose from the receiver."
"The primary sound is produced by a bow of nylon fish-line, which is rosined, and that's just threaded under the piano string and across it."
"The bow was brand new and had never been rosined before, and when it was ready I gently laid it across the strings at an angle, correcting the position of my hand."