A sequent is an expression of the form 

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$\phi_1, \phi_2,\!..., \phi_n \ent \psi.$
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$\phi_1, \phi_2,\!..., \phi_n$ are called premises. $\psi$ is called the conclusion.
The premises entail the conclusion.
This means that for any valid sequence, we can proof that the conclusion follows from the premises.