Unit symbols

Decided: first two letters of the name, lowercase. Exceptions: pace = p (most used, and "pa" would clash with Pa), vig = vg (vi is vis), grex = gx (gr = grain). No symbol may clash with an SI or imperial symbol, since both systems will be in use side by side.

Why: one simple rule is easy to learn and guess. Symbols must not clash with SI or imperial ones because both systems will be in use side by side for a long time. Pace gets a single letter because it's used most.

Advantage: a symbol can be guessed from its name (and the name from the symbol), and never means something else in SI or imperial.

Decided: where the first two letters make a common English word, use the first and last letters instead, as the moment does (mt): beat = bt (not be), iter = ir (not it), onus = os (not on).

Why: a review found that "add 3 it", "2 on of charge" and "1;3 be" read as English. opus keeps op: its first and last letters (os) would be the onus, and "op" isn't a common word on its own.

Advantage: no symbol reads as an English word, so a quantity can't be mistaken for text.

Unit Symbol Quantity
blink bl time
beat bt time
breath br time
moment mt time
chime ch time
pace p length
unc un length
dig di length
span sp length
ulna ul length
gress gs length
iter ir length
navis na length (sea and air)
parax px length (stars)
lib li mass
cub cu volume
ager ag area
tep °t temperature
tep absolute ta absolute temperature
vis vi force
opus op energy
vig vg power
pres pr pressure
riv ri current
onus os charge
imp im voltage
grex gx amount
lam la light
vox vo sound level
turn tu angle
  • chime: ch (the imperial chain is no longer used, so no real clash)
  • moment: mt (first and last letters: "mo" is the spoken word for 1,000, and mm is the millimetre)

Decided: temperature uses °t (eg 25 °t), for readings and differences alike, like °C. It's written with a space between the number and the degree sign, as SI writes 25 °C: 25 °t (and 25 °C, 77 °F when those appear). In typeset text the space is non-breaking, so a temperature can't be split across a line. Plain-ASCII fallback: te. A bare "25°" is fine where tep is the expected scale (eg weather).

Why: the degree sign means "a scale with a chosen zero", which is what the tep is (0 = freezing, like Celsius), and people already read 25 °C / °F that way. Lowercase because tep isn't named after a person (°C and °F are), and it avoids T (tesla). It's still two characters, so it fits the spirit of the rule. Written with a space like every other unit symbol (5;6 li, 29 im), and as SI and ISO 80000 write °C: the only SI symbols written straight after the number are the degree, minute and second of angle. Replaces the earlier rule of no space (25°t), which broke that consistency; a non-breaking space keeps the number and its unit on one line.

Advantage: readings look like the °C and °F people already know, can't be confused with the tesla, and temperatures follow the same spacing rule as every other unit.

  • Examples: 1;3 p tall, 2;6 li, 25 °t, 68 p/br, 29 im

Decided: all unit and prefix symbols are lowercase (t↑op, not tqOP or TQop).

Why: every prefix ends in q or c, so the boundary between prefix and unit is already clear. Capitals would clash with chemical elements (Cu, Be, Br, La), and all-capital units read as acronyms. Reusing SI prefix letters for powers of twelve (k = ×1,000;) was rejected: the same letter meaning a 1.728× different factor would cause errors where both systems are in use.

Advantage: there's nothing to remember about case, and no symbol can be mistaken for a chemical element or an SI prefix.

Decided: no unit symbol may start with q.

Why: in a prefix symbol, q is both quad's letter (4) and the "multiply" ending. If a unit symbol started with q, a prefixed symbol could be read two ways: "uqq..." could be uq (×10) followed by the unit, or uqq (×10^14) followed by the rest. c is safe, because no digit root uses it, so cu and ch are fine.

Advantage: every prefixed symbol can be read only one way, without checking a list of units.