This punctuation mark, indicated by a diagonal stroke (/) is also known as the slash, solidus, diagonal, and stroke. Among its many applications, the oblique is commonly used to separate alternatives (he/she, and/or), in certain abbreviations (A/Director for Acting Director), to indicate singular or plural (rock/s), in writing fractions (3/4), where it stand for the word upon, in writing element ratios (²³⁸U/²⁴⁸Pb), and NTS area designations (31 M/6), for reporting strike and dip measurements (125°/30°) and isotopic ages (2658 +9/-8 Ma), and instead of the word per (100 km/h).

Note that an en dash is usually used instead of the oblique when time expressions are not successive (1992–1997; January–June).

Use Cretaceous-Tertiary boundary (not Cretaceous/Tertiary boundary), K-Ar ratio (not K/Ar ratio), and K-Ar age (not K/Ar age).