Just about anything that holds something can take -ful: car/truck/bucket/basket/wheelbarrow/arm/mouth/drawer/closet etc Complicated? Adding -ful converts common words into amounts in an incredibly simple way. I have a carful of children. vs I have the number of children which fills my car. A: How much gravel did you bring? B1. 5 bucketfuls. vs B2. The amount that fills 5 buckets

I can think of two others. Just like a "spoonful" is enough of something to fill a spoon, a "handful" is enough to fill a hand and a "bucketful" is enough to fill a bucket.

I found many such nouns by searching on "words ending in 'ful'" but they are all quite similar. Every adjective can be used as a noun: "the good, the bad, and the awful", "the thoughtful, the hopeful, and the doubtful". NOUN -> NOUN mouth - mouthful glass - glassful faith - faithful (also an adjective) arm - armful wonder -> wonderful wish -> wishful skill -> skillful NOUN -> ADJECTIVE thought - thoughtful hope - hopeful fright - frightful awe - awful care - careful glee - gleeful pain - painful meaning - meaningful VERB -> ADJECTIVE forget - forgetful resent - resentful

Although I accept your claim that English is (generally) complicated, in this case, as DavidK explains, it is unusually simple and useful. The idea extends to adjectives too, though it does not denote quantity : beautiful is ‘full of beauty’, wonderful is ‘full of wonder’ (though ‘wonder’ usually means something slightly different), and careful is ‘full of care’. In these cases the noun is turned into an adjective.