In the broad sense, it is the inner, fleshy portion of a mushroom's basidiocarp, or fruit body.
In essence, the trama is the tissue that is commonly referred to as the "flesh" of mushrooms and similar fungi.
It is similarly interior, connective tissue, but it is more specifically the central layer of hyphae running from the underside of the mushroom cap to the lamella or gill, upon which the hymenium rests.
In the agarcoid type, the central trama's hyphae usually run parallel to each other, with a clear boundary area called a sub-hymenium followed by the hymenium itself on the outer layer facing the environment.
[3] This is related to the basidiocarp trama being "filler" tissue and that analogously the woof yarn in weaving is sometimes called "fill".