Private placement (or non-public offering) is a funding round of securities which are sold not through a public offering, but rather through a private offering, mostly to a small number of chosen investors. Generally, these investors include friends and family, accredited investors, and institutional investors. Placement agents help find investors.
PIPE (Private Investment in Public Equity) deals are one type of private placement. SEDA (Standby Equity Distribution Agreement) is also a form of private placement. They are considered to present lower transaction costs for the issuer than public offerings.