ד (or Dalet, Daled) The fourth letter of the Hebrew alphabet, ד Daleth symbolizes "a door." When adapted to Greek, it became the letter Delta (a triangle).

Daleth is related with:

• The four elements of the physical world: fire, air, water, and earth
• The four states of the matter: solid, liquid, gaseous, combustion
• The four atoms in Alchemy: hydrogen, carbon, nitrogen, oxygen
• The four worlds of Kabbalah: Atziluth, Briah, Yetzirah, and Assiah
• The four letters of the name of God: Iod, Hei, Vau, Hei
• Etc

In Kabbalah, the letter Daleth represents a youth, the terrestrial man, who receives charity from his heavenly man, his letter Gimel. For this, Shaddai El Chai must stand at the open door (Daleth) of the entrance of his house (physical body).

The Kabbalistic value of Daleth is 4.