How to get the week day name from a date?

Nearly ten years late to the party, but I think it's neccessary to enhance @Zohaib 's answer as it's result depend on the language of the client. If you display the week day name to a user, it's absolutely fine, but if your code depends on it, I'd rather control the language like so:

SQL> SELECT TO_CHAR(date '1982-03-09', 'DAY', 'NLS_DATE_LANGUAGE = ENGLISH') day FROM dual;

DAY
---------
TUESDAY

SQL> SELECT TO_CHAR(date '1982-03-09', 'DY', 'NLS_DATE_LANGUAGE = ENGLISH') day FROM dual;

DAY
---
TUE

SQL> SELECT TO_CHAR(date '1982-03-09', 'Dy', 'NLS_DATE_LANGUAGE = ENGLISH') day FROM dual;

DAY
---
Tue

SQL> SELECT TO_CHAR(date '1982-03-09', 'DAY') day FROM dual;

DAY
---------
TUESDAY

SQL> SELECT TO_CHAR(date '1982-03-09', 'DY') day FROM dual;

DAY
---
TUE

SQL> SELECT TO_CHAR(date '1982-03-09', 'Dy') day FROM dual;

DAY
---
Tue

(Note that the queries use ANSI date literals, which follow the ISO-8601 date standard and avoid date format ambiguity.)