suyas
/ˈsuʝas/ · B2 · pron
theirs, their, to them
suyas comes from Latin suus, one's own, the same root as the sui in suicide
Suyas is the feminine plural of suyo and refers to several feminine things that belong to him, her, them or formal you (usted). Example: las llaves son suyas means the keys are theirs. The -as ending matches a feminine plural noun.