The central focus of inspiration and devotion for Buddhists
is the Triple Gem (also known as the Three Treasures and
the Three Refuges). These three are Buddha, Dhamma
(Dharma), and Sangha.

Buddha means ‘Enlightened One’ or ‘Awakened One,’ and
is generally used to refer to the founder of Buddhism. There
have been other Buddhas before him, however, and will be
other Buddhas in the future.

The word Dhamma (in Sanskrit, Dharma) is often used to
refer to the Buddha’s teachings, but it also means the eternal
Truth which the teachings convey to us. Dhamma is threefold:
the Dhamma that we study, that which we practice, and the
Dhamma of Realization.

Sangha literally means ‘community’ or ‘assembly.’ The word
has two meanings in proper Buddhist usage: the community of
disciples (whether ordained or not) who have gained Realization
of any of the stages of Awakening; and the community of ordained
disciples–bhikkhus (monks) and bhikkhunis (nuns).

Source: http://mettajon.tripod.com