Tefillin:
The form is an Aramaic plural (the Hebrew plural would be tefillim), whose singular would be tefillah, “prayer,” similar to tehillim “Psalms, ” plural of tehillah “psalter.”* However, the plural tefillin is used for both, as in tefillin shel yad “tefillin of hand,” tfillin shel rosh “tefillin of the head.” The Jews of Baghdad had a double plural form: tefillimot to refer to more than one pair.
The English-Greek word phylactery means “guard-amulet,” just as tallit means “protecting-cover,” from the root T-L-L (Daniel 4:9; Nehemiah 3:15). Indeed, some anthropologists consider tefillin to allude to snake, a universal symbol of medicine and protection (Compare 2 Kings 18:4). The biblical name is ToTafot (Deuteronomy 6:8) “frontlet, pendant, amulet.”
*Or “song of praise (to God),” as in Psalms 145:1; from the root H-L-L, “ululate, cheer or praise.”
Yona Sabar is a professor of Hebrew and Aramaic in the department of Near Eastern Languages & Cultures at UCLA.