Define Explain plan?

Explain plan displays the execution plan of SQL statement that is going to be executed by the database.
This plan will be specified by the component called optimiser.Generaly it displays below information:
a.Number of Amps
b.Amount of spool memory it is occupying.
c.Number of Rows its affecting.
d.Type of Join strategy it is taking.
e.Time it takes to execute.
f.Locks it is Using etc.

Syntax : EXPLAIN
Example : EXPLAIN SEL * FROM PARTY;