interface

This term is defined in ECSS-E-ST-35C Rev. 1 as
common boundary involving a direct interaction between two or more systems, subsystems or components

This term is defined in ECSS-E-ST-31-04C as
reader or writer

This term is defined in ECSS-S-ST-00-01C as
boundary where two or more products meet and interact

This term is defined in ECSS-E-ST-50C as
description of the connection between real or abstract objects