[Rusty]

There are abbreviations for the days of the week in Spanish, but VARY from place to place and author to author.

lun. (L.)
mart. (M., m, k)
miérc. (Mi., m, x)
juev. (j., J.)
vier. (vnes, V.)
sáb. (S.)
dom. (D.)


I've seen watches that give 3-letter abbreviations, but this could be because English, the other language, had 3-letter abbreviations.

L, M, X, J, V, S, D
L, K, M, J, V, S, D

Lu, Ma, Mi, Ju, Vi, Sa, Do / LU, MA, MI, JU, VI, SA, DO