Dhamma is the profound truths of human life pointed out by the Awakened Ones (Buddhas) and other liberated spiritual guides. While the wording is conditioned by time and place, true Dhamma transcends our differences & distinctions. A life wholly given to Dhamma is a life without suffering. This is the pinnacle of our natural duty according to the Law of Nature. The Dhamma of Dhamma.
A Dhamma refuge such as ours seeks to live in harmony with Dhamma and to support others in doing so, with whatever skilful means available to us. We are especially inspired by the expressions of Dhamma found in the Păli suttas of early Buddhism, as preserved by the Theravada school, yet respect all teachings of genuine selflessness. However, Dhamma is less the words in the texts than the living realities pointed to by the best of those texts. Dhamma is also the Nature surrounding & permeating us. Living intimately with non-human nature -- such as in midst our woods, fields, & streams -- can inspire & support us in experiencing & seeing Dhamma more deeply & fully.
Ajahn Buddhadasa's most concise and inclusive definition of Dhamma:
"Dhamma" has many meanings; however, its essence is the duty which is performed correctly regarding the practitioner's situation, according to the Law of Nature, leading to peace for everyone, no matter the time or place." (From his Eightieth Birthday Memorial Book)
For more on this, please see Dhamma is Duty, Duty is Dhamma.