Longman Dictionary of Contemporary English - commitment

~ n 1 a promise to do something or to behave in a particular way  (Jim's afraid of emotional commitments.)  (a commitment to equal pay and opportunities) 2 the hard work and loyalty that someone gives to an organization, activity etc  (I was impressed by the energy and commitment shown by the players.)  (Her commitment to work is beyond question.) 3 something that you have previously arranged to do at a certain time and that prevents you from doing anything else at that time  (She's got several teaching commitments over the summer.) 4 an amount of money that you have to pay regularly and that prevents you from spending your money on other things  (a heavy mortgage commitment) 5 especially AmE the use of money, time, people etc for a particular purpose  (The plan involves commitment of money and staff time.)