What is the meaning of Kaksikko?

twosome, two, duet, duo, pair, doublet, twin (group of two; two similar or closely related objects, entities etc., or a group of two people, not necessarily related in any way)

dual, dual number (grammatical number of a noun marking two of something)

double, tandem

twayblade (orchid of the former genus Listera, now considered part of Neottia)

twin

Source: wiktionary.org