Many writing in the field of biblical studies and its cognate disciplines will have reason to use a prime symbol: ′. This single mark is used in various contexts to indicate a number of different things. The following noncomprehensive list identifies some of the more common.

• A prime symbol can stand for the word feet, as in 3.5′. (The double prime is used in place of inches in such contexts, e.g., 3′ 6″.)
• A prime symbol is often used to mark the second of two related units in a concentric or chiastic structure (e.g., G and G′) or the lines in a poetic structure (A B B′ A′).
• Use of a prime symbol with the line numbers of an ancient text generally indicates that the numbering is relative. That is, scholars do not know how many lines are missing from the beginning of a broken text and start counting lines from the extant portion (e.g., lines 14′–17′).
• The Septuagint witnesses attributed to Aquila, Theodotion, and Symmachus are most frequently abbreviated by appending a prime symbol to the first letter of each name in Greek, thus α′, θ′, and σ′, respectively.

Authors use a variety of characters where a single prime symbol is intended. Popular substitutes include a single quotation mark ('), which often is automatically formatted into a typographer’s closing quotation mark (’); an acute accent sans accompanying letter (´); or a Greek numeral sign (ʹ). None of these characters should be used in place of the proper prime character: ′ (Unicode 2032).

This may seem a minor matter, but sometimes it matters a great deal. For example, imagine a book in which multiple Septuagint specialists contribute essays that reference at various places the three witnesses. Although all authors use the standard abbreviations, some employ a single quotation mark for the prime, some an acute accent, some a Greek numeral sign, and some the actual prime symbol. How would a curious reader with access to an e-book search and locate all the abbreviated references to Aquila? Searching for one of the combinations would produce incomplete results; having to search for all four would no doubt generate extreme irritation.

The solution to the problem is simple: authors should use the technically correct prime symbol whenever a prime is needed. It does not matter that other symbols resemble the prime; visual similarity is not the issue. Consistency and searchability are the important factors to consider, and those factors weigh heavily in favor of using the proper symbol for the job.

If you have difficulty remembering where in your symbols palette or list of characters the prime symbol is located, do what we plan to do: copy and paste it from the first sentence of this post.