role

n 1: the actions and activities assigned to or required or

expected of a person or group: "the function of a

teacher"; "the government must do its part" or "play its

role" or "do its duty" [syn: {function}, {office}, {part}]

2: an actor's portrayal of someone in a play; "she played the

part of Desdemona" [syn: {character}, {theatrical role}, {part},

{persona}]

3: what something is used for; "the function of an auger is to

bore holes"; "ballet is beautiful but what use is it?"

[syn: {function}, {purpose}, {use}]

4: normal or customary activity; "what is your role on the

team?"

hole

The absence of an {electron} in a

{semiconductor} material. In the {electron model}, a hole can

be thought of as an incomplete outer electron shell in a

doping substance. Holes can also be thought of as positive

charge carriers; while this is in a sense a fiction, it is a

useful abstraction.

(1995-10-06)