cardinal number with emphatic particle
Analysis. cattālīsa + api; the enclitic emphatic particle api ('even, also') is affixed to the cardinal number cattālīsa, emphasizing 'forty' or 'as many as forty'.
Etymology. cattālīsa is a compound of catta ('four') + ālīsa (a group or set of ten). The root is Indo-European *kwetwor- (four; cognates: English four, Latin quattuor, Greek tessares). The element ālīsa is obscure but may relate to an old word for a decade or group. The number system combines the base-four element with a multiplier to express forty.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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