The Subindex flag (>) works as a subindex entry flag only if you have issued an .INDEX or .ENTRY command. Subindex entries marked with this flag are collected and alphabetized below the primary entry to which they refer. The Subindex flag indicates that the next word or phrase will be placed on the following line of the index, indented two characters to the right of the preceding entry.
1 – Default
Recognition is turned on only within .INDEX and .ENTRY commands.