Q:

Let's synonymize a few plural, unnecessary tags

We have a few tags which should be synonymized!
identifiers (51) has the same tag wiki as identifier (641), and are synonymous:

An identifier is a name that identifies either a unique object or a unique class of objects.

Next is the directories (446) tag, which simply just says the following in its excerpt:

Use the [directory] tag instead

It should be synonymized into directory (5,069).
The direction (315) tag is a very meta tag, and doesn't have a tag excerpt or tag wiki to help users use the tag properly. It should / could be synonymized into directions (190), which includes a helpful tag excerpt and tag wiki.
cipher (0) was synonymized into encryption (14,259), but ciphers (67) wasn't, and there is no tag excerpt or wiki for the tag to demonstrate differences between the tag and ciphering. It should be synonymized into encryption as well.
Unfortunately, I myself do not have enough tag score in any of the fields to propose the tag synonyms.

A:

identifiers should have been retagged and now has no more questions.
direction tag has been improved and is now no longer synonymous to directions, so it can live.
I've also went through and retagged what's still there of ciphers, and they now point to the correct tags (ssl, tls, aes et cetera). ciphers now has no more questions.
However, the directories tag still has to be dealt with.

As of Fri May 01 15:48:23 2015 UTC, directories is synonymized to directory thanks to animuson♦.

