Basic vocabulary needed when dealing with contracts:

agreement: an arrangement between two or more people, countries etc; contract.
appendix: additional or supplementary material at end of contract, book etc.
arbitration: settlement of a dispute by a person chosen by both parties - to arbitrate v.
article: a particular statement or stipulation in a contract etc; clause.
clause: a particular statement or stipulation in a contract etc; article.
condition: anything necessary before the performance of something else.
force majeure: superior, power; unforeseeable event excusing one party from fulfilling contract.
fulfil: to satisfy a condition; to complete the required task; to fulfillUS.
herein: in here; in this (document etc).
hereinafter: to this (document etc) [eg: attached hereto].
hereto: in the following part (of this document etc).
heretofore: up until now; until the present; before this.
in behalf of: in the interests of (person etc); for (person etc); on behalf ofUK .
null and void: invalid; without legal force; not binding.
on the one hand: on one side - on the other hand on the other side.
party: the person or persons forming one side of an agreement.
stipulate: to specify as an essential condition - stipulation.
terms: conditions or stipulations.
warrant: to give formal assurance; to guarantee.
whereas: it being the case that; in view of the fact that [in introduction to contracts].

* Answer-key for the exercise on unit/point "1.2  PAY & BENEFIT" :

Baja por enfermedad: sick pay
Baja por maternidad: maternity leave
Cobertura odontológica: dental plan
Coche de empresa: company car
Cantina: subsidized canteen
Cuenta de gastos: expense account
Descuento para empleados: employee discounts
Emision de acciones: stock options
Empleo compartido: job sharing
Horario flexible: flexible hours
Indemnización por despido: redundancy package
Plan de pensiones: pension scheme
Retribución en especie: fringe benefits
Retribución variable: performance-related benefits
Salario anual: annual salary
Servicio de guardería: childcare facilities
Seguro de vida: life insurance
Salario mínimo: minimum wage