After a motion has been made, another member who wishes it to be considered says, “I second the motion.” or, “I second it,” or even, “Second!” – without obtaining the floor. RONR (11th ed.). p. 35 ll. 4-5
If no member seconds the motion, the chair must be sure that all have heard it before proceeding to other business. In such a case the chair normally askes, “Is there a second to the motion?” RONR (11th ed.). p. 35 ll. 15-18
The requirement of a second is for the chair’s guidance as to whether he should state the question on the motion, thus placing it before the assembly. Its purpose is to prevent time from being consumed by the assembly’s having to dispose of a motion that only one person wants to see introduced RONR (11th ed.). p. 36 ll. 26-31.