Principal English Translation: 

a suffix that signifies affiliation; e.g. a person from a place with a name ending in "-co"; plural = -cah (-ca); e.g. Atlixcatl = a person from Atlixco; because this conveys an identity associate with a place, it can be an ethnic identifier; it can also be a suffix that indicates a title for a person who holds a certain position in government, e.g. Tlacochcalcatl

Attestations from sources in English: 

-ca or -cah = the plural form