What does it mean to “uplift” a supergravity solution to higher dimensions?

What does it mean to "uplift" a supergravity solution to higher dimensions? This is a common term used in the literature but I cannot understand it. A very common example is "uplifting d-dimensional solution to 11-dimensional supergravity or M-theory". Is there some simple example?

An uplift is the opposite of a dimensional reduction. Take for example the relation between (the low-energy limit of) M-theory and type IIA supergravity: the former is eleven-dimensional, while the latter lives in ten dimensions. If you find a solution of M-theory, you can get its equivalent in type IIA by Kaluza-Klein reduction. For example, the eleven-dimensional metric $G_{MN}$ gives rise to the ten-dimensional metric $G_{mn}$, a gauge field $G_{m,10}$ and a scalar $\Phi=G_{10,10}$ (the dilaton). Since both descriptions are completely equivalent, one can also start in ten dimensions, solve type IIA supergravity and then construct the eleven-dimensional fields. This is referred to as "uplifting". While the details of course vary from case to case, the principle is always the same.