-dor (mass) or -dora (fem) is like English -tor. It indicates a person or thing that usually does the action. A refrigerator is a machine that refrigerates. Una secadora es tuna máquina que sea. The suffix is usually preceded by -a-, but it may be preceded by -i- or -e- depending on the verb conjugation in Spanish / Latin. It may also be preceded by a consonant, like actor (feminine actriz — “actress” in English). The T may also assimilated "precursor" -- forerunner.

I think I got it. Thanks a lot.

by the way, all verbs in spanish ends with "R" by rule. regards

¡Muchas Gracias Rodrigo! Español es interesante paro muy dificil. Thank you very much Rodrigo! Spanish is interesting but very difficult. Your answer is very helpful.

the verb in those words are: rasurar, refrigerar, secar. and other examples podar, limpiar, tostar, licuar the instrument or equipment to run these verbs you have to add: dora or dor and eliminate the last r of the verb dor (mass) or -dora (fem) like Phil said before rasuradora, refigerador, secadora, podadora, limpiador, tostador, licuadora