Definitions for "Tefillin"
small black leather cubes containing parchment scrolls inscribed with the Shema and other Biblical passages; bound to the head and forearm, customarily worn by men during the morning prayer service
"phylacteries" These are worn by males at the weekday morning (Shacharit) services. The boxes have leather thongs attached and contain scripture passages. One box is placed on the head, the other is placed on the left arm, near the heart. The biblical passages emphasize the unity of Yahweh and the duty to love Yahweh and be mindful of him with "all one's heart and mind" (Shemot / Exodus 13.1-10, 11-16; Devarim / Deuteronomy 6.4-9; 11.13-21)
Tefillin are two black leather cubes (boxes) that are worn by many Jewish men while at morning prayer.