Capable of being amassed or accumulated in quantity; able to be gathered together in large amounts.
From the verb amass (from Middle English, from Old French amasser: a- 'to' + masse 'mass') with the suffix -able (from Latin -abilis, meaning 'capable of being'). The word indicates capacity for accumulation.
The -able suffix is one of English's most productive endings—it turns almost any verb into 'capable of being done,' which is why we can say touchable, washable, amassable, or even made-up words like 'spreadable' for butter.
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