How about eta? The n with the long end.

2π

η


see Entities for Symbols and Greek Letters

What's wrong with just 2π, as Lucid suggests? η is a symbol for efficiency in engineering.

thanks Rick. Didn't realize that using font face Times New Roman gives better symbols when used in conjunction with the symbol codes given in the above link.

without font face Times New Roman, 2*pi looks like:
2π

but with font face Times New Roman, it looks like:
2π


Here are some more symbols (try copying and pasting into your post):


ƒ Α Β Γ Δ Ε Ζ Η Θ Ι Κ Λ Μ Ν Ξ Ο Π Ρ Σ Τ Υ Φ Χ Ψ Ω α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ ς σ τ υ φ χ ψ ω ϑ ϒ ϖ ℘ ℑ ℜ ™ ℵ ← ↑ → ↓ ↔ ↵ ⇐ ⇑ ⇒ ⇓ ⇔ ∀ ∂ ∃ ∅ ∇ ∈ ∉ ∋ ∏ ∑ √ ∝ ∞ ∠ ∧ ∨ ∩ ∪ ∫ ∴ ∼ ≅ ≈ ≠ ≡ ≤ ≥ ⊂ ⊃ ⊄ ⊆ ⊇ ⊕ ⊗ ⊥ ⋅ ⌈ ⌉ ⌊ ⌋ 〈 〉 ◊ ♠ ♣ ♥ ♦



∞

Oh? Thing is, all of them are really taken. Lots have multiple meanings. So would another letter (greek or other) be better? The reason for 2*pi is that it is so often taken as (2*pi) that it would be much easier to not need to deal with the 2 factor. Just like we use omega to mean 2*pi*f.

my bad. I thought you were looking for ways to post greek symbols.

No problem. Thanks anyway. I'm looking at reasons to declare among the math community a new symbol for (2*pi).

It seems a bit unnecessary. 2π is okay with me. (Besides, I've become attached to it in trigonometry and complex analysis, so I would like to keep it for aesthetic purpose. )