italics: mathematical and scientific material

Follow the guidelines below for the use of italics in mathematical, statistical and scientific contexts.

Genera and species

Italicize the scientific (Latin) names of genera and species in botanical, zoological and paleontological matter:

• The sugar maple (Acer saccharum) is a member of the family Aceraceae.

Do not italicize the names of the larger subdivisions (phyla, classes, orders, families and tribes):

• The order Primates includes modern man (Homo sapiens).

Letters in algebra and geometry

Italicize letters designating unknown quantities and constants, lines, etc., in algebraic, geometric and similar matter:

• Let n be the number of molecules …
• 5x × a2 – 2ab

Note in the second example that no space is left between the numerical coefficients and the variables, and that the italics help to differentiate between the variable x and the multiplication sign. Correct spacing and italic type also help to distinguish between algebraic variables and SI/metric symbols:

• 10x m
• 6a cm
• 10b L

Quantity symbols

Italicize quantity symbols such as l for length, m for mass and v for velocity in order to distinguish them from unit symbols such as “L” for litre, “m” for metre and “V” for volt, which are normally printed in roman type:

• 60 N = m × 12m/s²
• m = 5 kg

(N = newton, m = mass, and m = metre)

Chemical prefixes

Italicize Latin prefixes and Greek and Roman letters used as prefixes to the names of chemical and biochemical compounds:

• cis-dimethylethylene
• ß-lactose
• N-acylneuraminic acid
• M-xylene

Greek and Roman letters in statistics

A number of Greek and Roman letters used in statistical formulas and notations are italicized:

• P (probability of)
• µ (population mean)
• Ó (population standard deviation)
• Ó² (population variance)