Guide for the Use of the International System of Units (SI)

8.9 Massic, volumic, areic, lineic 
 
Reference [4: ISO 31-0] has introduced the new adjectives “massic,” “volumic,” “areic,” and 
“lineic” into the English language based on their French counterparts: “massique,” “volumique,” 
“surfacique,” and “linéique.” They are convenient and NIST authors may wish to use them. They are 
equivalent, respectively, to “specific,” “density,” “surface . . . density,” and “linear . . . density,” as 
explained below. 
(a) The adjective massic, or the adjective specific, is used to modify the name of a quantity to indicate the 
quotient of that quantity and its associated mass. 
Examples: massic volume or specific volume: υ = V / m 
 
 
 
massic entropy or specific entropy: s = S / m 
 
(b) The adjective volumic is used to modify the name of a quantity, or the term density is added to it, to 
indicate the quotient of that quantity and its associated volume.
Examples: volumic mass or (mass) density: ρ = m / V 
 
 
 
volumic number or number density: n = N / V 
 

---

Guide for the Use of the International System of Units (SI) 
 
31 
Note: 
Parentheses around a word means that the word is often omitted. 
(c) The adjective areic is used to modify the name of a quantity, or the terms surface . . . density are added 
to it, to indicate the quotient of that quantity (a scalar) and its associated surface area. 
Examples: areic mass or surface (mass) density: ρ
A
 = m / A 
 
 
 
areic charge or surface charge density: σ = Q / A 
 
(d) The adjective lineic is used to modify the name of a quantity, or the terms linear . . . density are added 
to it, to indicate the quotient of that quantity and its associated length. 
Examples: lineic mass or linear (mass) density: ρ
l
 = m / l 
lineic 
electric 
current 
or 
linear electric current density: A = I / b