I answered this a couple of weeks ago...
"saint (n.) early 12c., from Old French saint, seinte "a saint; a holy relic," displacing or altering Old English sanct, both from Latin sanctus "holy, consecrated" (used as a noun in Late Latin; also source of Spanish santo, santa, Italian san, etc.), properly past participle of sancire "consecrate" (see sacred). Adopted into most Germanic languages (Old Frisian sankt, Dutch sint, German Sanct).
"Originally an adjective prefixed to the name of a canonized person; by c.1300 it came to be regarded as a noun. Meaning "person of extraordinary holiness" is recorded from 1560s."
In a word, it means "holy". That's why, during the course of (cough) Holy Mass, you see "Spirítui Sancto" (Holy Ghost), "Dómine sancte" (Holy Lord), "sanctum Angelum" (Holy Angel), "sanctis Apóstolis" (Holy Apostles), "Sancta sanctórum" (Holy of Holies),"sanctum Evangélium" (Holy Gospel), "Ecclésiæ suæ sanctæ" (His Holy Church), "plebs tua sancta" (Thy Holy People) etc, etc...
There are lots of "St. Saviour" parishes and schools, it means holy Savior.
See the problem is an angel is NOT A PERSON ...