One letter makes all the difference

There is often confusion over the words dependent and dependant.

Dependant is a noun:

A dependant is a person, often a child or a partner, who is supported by someone else; a person who relies on another, especially a family member, for financial support.

Examples:

• All Palace staff and their dependants must be ready to leave when the revolution comes. 
• He has eight dependants of varying ages from his three marriages.

Dependent is an adjective:

Dependent means contingent on, relying on, supported by, addicted to, and subordinate to.

Examples:

• The ferry to Great Barrier Island is dependent on the weather for a safe crossing. 
• Tokelau is one of New Zealand’s dependent territories.
• She is dependent on her friend to help write her essays.
• Plants are dependent on light for survival.
• He is dependent on his mother even though he’s over thirty years old.
• Many homeless people are dependent on drugs and alcohol to get through the day.
• In the US, the individual states are dependent on the federal government to some extent.
• A dependent clause cannot stand alone as a complete sentence.

An example for both:

• A child is dependent (adjective) on his or her parents; therefore, a child is a dependant (noun) of his or her parents.

Footnotes:

• There’s no problem here if you’re American: both the noun and the adjective are usually spelled the same (dependent).
• There’s no such word as independant.  It’s a misspelling of independent.