Simplex (adjective)
definition:
allowing communication in only one direction at a time, or in telegraphy allowing only one message over a line at a time
example:
"simplex system"
Simplex (adjective)
definition:
having only one part or element
example:
"a simplex word has no affixes and is not part of a compound--like `boy' compared with `boyish' or `house' compared with `houseboat'"
