(a) "person" shall mean one or more individuals, partnerships, corporations or associations;
(b) "proceeding" shall mean any quasi-judicial or administrative procedure instituted by a written application by a person to a body or officer, by a notice of assessment given by a body or officer to a person, by a written complaint addressed by a body or officer or transmitted by a body or officer to a person, or by a notice of any hearing before a body or officer whether or not such hearing is prescribed by statute. 3. This section shall not apply to preliminary investigations.