To cause (someone) to be acquainted (with someone else).
To add (something) to a system, a mixture, or a container.
To bring (something) into practice.
To make (something or someone) known by formal announcement or recommendation.
To let someone or something come in; to admit someone or something in.
To associate with.
To divulge one's inner thoughts to (someone), making oneself emotionally vulnerable to them; to open up to (someone).