The affix ghañ comes after the roots ci 'to collect' and ka is the substitute of the initial ca in these senses viz. - 1. 'a dwelling' 2. 'a fire on the funeral pile' 3. 'the body' 4. 'collection'.,
That in which people dwell (निवसति) is called निवासः or 'dwelling'. That which is gathered together (चीयते) is called चिति or 'funeral pile'. शरीर means the body of all living beings; and उपसमाधान means making a heap. Thus निकाय 'a dwelling'; as in काशीनिकायः 'Kasi-dwelling'; आकायमग्निं चिन्वीत 'let him arrange the akaya fire i.e. the funeral fire'; कायः 'body', as अनित्यः कायः 'a perishable body'; महान् गोमयनिकायः 'a heap of cow-dung'.
Why do we say 'when having these senses'? Observe चयः 'gathering'. Why is not this rule applied in महान् काष्ठनिचयः 'a large heap of wood'? Here multiplicity is expressed and not collection or aggregation.,