"Letted steam" is not a commonly used phrase, but its spelling can be explained through phonetic transcription. "Letted" would be pronounced as "let-ted" with a short "e" sound and a slight emphasis on the second syllable. "Steam" would be pronounced as "steem" with a long "e" sound. Together, the phrase would sound like "let-ted steem." While this phrase may not be well-known, breaking down its spelling through phonetics can help with understanding other less common words and phrases.
The phrase "let off steam" is a commonly used idiom in English, and "letted steam" appears to be a variation of this expression. Both phrases essentially mean the same thing: to release or express one's built-up emotions, frustrations, or energy.
In terms of etymology, the word "let" originated from Old English "lǣtan", which means "to allow" or "to permit". Over time, its meaning expanded to include releasing or allowing things to escape. In this context, "let" refers to allowing steam or pressure to be released.
The term "steam" originates from Old English "stēam", which refers to the water vapor that is formed when water is heated to its boiling point. The word "steam" has been traced back to the Proto-Germanic root word "staumaz", meaning "vapor" or "dust".