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  1. The Name of the Fraternity is represented by the capital form of the Greek letters Sigma (Σ), Phi (Φ), Delta (Δ) which stand for Science, Friendship and Duty.

  2. The Symbol of the Fraternity is the Castle.

  3. The Colors of the Fraternity are Red and Black.

  4. The Flower of the Fraternity is the American Beauty Rose.

  5. The Motto of the Fraternity is "Pro Bono Professionis", which is translated "For the Good of the Profession".

  6. The Pledge Button, illustrated below, is described as: "A red triangular background on which is a black Castle, the whole bordered in gold".

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  7. The Membership Badge is described as: "A triangle having concave corners on which are superimposed three smaller triangles having concave sides and having their vertices at the center of the badge on which is placed a ruby. The smaller triangles, which contain the letters Sigma, Phi and Delta, are black, the background between them being white. A gold star is located near each of the vertices of the large triangle. The border may be engraved gold or may be jeweled. The crown pearl badge has four pearls on each side of the badge. The ruby point badge has two rubies and two pearls on each side, the pearls being in the middle and the rubies at the outside".

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  8. The Membership Card, containing the name of the member, his school, the date of initiation and the assigned General Number is given to each new Member at the time of initiation. On the obverse side, the printing is superimposed on a representation of the Seal of the Fraternity. On the reverse side, the Code of Ethics of the Fraternity is carried. The card is signed by the Grand President, the Executive Secretary and the member.

  9. The Membership Certificate, giving the name of the member, his Chapter, his General Number, and the date of initiation, is given to each member. This Certificate is signed by the Grand President, Executive Secretary, Chapter President and Chapter Secretary.

  10. The Fraternity Flag, illustrated below, is 4' x 6' cotton bunting or nylon. The design is black letters and gold Castle on a red field. This is a standard flag, that is, reading correctly from left to right on one side and in reverse on the other.

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Gules, a pall or, between, in chief two retorts crossed argent, in dexter base a quill sable surmounting a key in saltire, of the third, in sinister base a hammer fesswise of the fourth debruising a compass, points downward, of the third; over all the escutcheon of pretense, azure, charged with a castle or, masoned sable, with a bordure argent.

Crest, over a duke's helmet and a torse of the colors, a dexter cubit arm, proper, grasping a thunderbolt, winged or

Mantling: Gules doubled, or
Supporters: Two lions, rampant, proper
Motto: Sigma Phi Delta, in upper and lower case Greek letters


The logotype of Sigma Phi Delta fraternity was adopted on December 17, 2002. It embodies our symbol, the Castle, our letters ΣΦΔ, and our profession ”Engineers.”

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The slogan of Sigma Phi Delta Fraternity was adopted on November 19, 2002, and recognizes us as the only international engineering fraternity: Sigma Phi Delta, The Premier International Fraternity of Engineers.