Thamê is the Law of Order of the universe, the Cosmic Harmony of Dea and Celestial Music of the cosmos that points to the nature of the manifest world. Thamë is the nature of the world that is the Great Harmony that unites us and keeps the corporeal world structured and functioning.
When capitalized, Thamë is meant to portray this greater Nature of reality, and when it is a lower case thamë it is meant to one's own personal connection to harmony and order, one's one true nature that comes of Dea and the Higher Order of the cosmos.
There is a "Wheel of Thamë" as well, which is separate from the previously mentioned "Wheel of Werdë". The Wheel of Thamë shows the order of time and marks the major passages of time within a year, and so has eight spokes on in, showing the solstices, the equinoxes, and the cross quarter days. This is to show the order of the year, which connects one to the greater Order of Thamë.