M
- Maestre: a master of some subject or occupation
- Maestre de campo (maese de campo): field commander; the second in command after the general
- Maestresala: head of the household
- Maravedí, maravedíes: an archaic basic unit of Spanish currency. In the sixteenth century it was not a physical coin
- Marqués: A person bearing this title of nobility had a lower status than a duque but higher than a conde
- Mayorazgo: an estate inherited by primogeniture
- Mayordomo: a foreman or custodian of public or private property
- Mercador (mercader): a merchant
- Méritos y servicios: a statement presented to obtain royal favor in which the deeds of one's ancestors (méritos) and one's own deeds (servicios) are enumerated