relation

1 : an aspect or quality (as resemblance or causality) that connects two or more things or parts as being or belonging or working together, as being of the same kind, or as being logically connected <the strong relation between genotype and phenotype—Anne M. Glazier et al>
2 : the attitude or stance which two or more persons or groups assume toward one another <race relations>
3 a : the state of being mutually or reciprocally interested (as in social matters) b relations pl : sexual intercourse <testified that relations had occurred—Newsweek>