Spanish weekday single-letter codes use X for miércoles rather than an M or another letter; the full set is L, M, X, J, V, S, D. Author @davidgomes (2026-08-01) calls out the oddity of X for miércoles as a recurring, surprising detail that haunts their Spanish study each week.
Spanish single-letter day abbreviations are: L = lunes, M = martes, X = miércoles, J = jueves, V = viernes, S = sábado, D = domingo.
The single-letter code abbreviations for the days of the week in Spanish are L (lunes), M (martes), X (miércoles), J (jueves), V (viernes), S (sábado), and D (domingo).
X for "miércoles"??
My studying of Spanish is haunted by these random things every week.