English
lengthful
From length + -ful.
Formed from length + -ful
Proto-Indo-European *dlongʰos ‘long’
…
Proto-Germanic *langiþō ‘longness’
Proto-West Germanic *langiþu ‘longness’
Old English lengþ
Middle English lengthe
English length
Today it means
adj long
Language periods are conventional ranges, not dates for this word.
Etymograph / lengthful