Uniform load is a load distributed uniformly over a part or over the entire length of a beam; live loads such as people, furniture on the floor or snow on the roof are examples of a uniform load is.
Book definition: a load distributed the same over each square foot of an area or the same along each linear foot of the beam
Definition – Beam
Beam – A beam is a straight structural member that acts primarily to resist nonaxial loads.
The book definition is more precise. The examples be fine. A disturbed load is a uniform load which acts on only part of the beam.
What do you mean by nonaxial loads?
Definition – Girder
Girder – A horizontal beam that supports other beams, a very large beam, especially one that is built up from smaller elements.