Question

what does trans elimination reaction mean?

Answer 1

Trans elimination reaction is nothing but E2 Eliminarion reaction.
As you may know, this is a one step mechanism. It is a single step elimination with a transition state. It is typically undergone by primary substituted alkyl halides ,but it is possible with some secondary alkyl halides and other compounds. The reaction rate is second order because it is influenced by alkyl halide and the base.

Always elimination reactions tend to stable products.