GG5, ルミナス: "【日英比較】 日本語では特にビルなどの借用者をいうが, 英語では広く一般の土地･家･ビルの賃借人をいう."

Hmmmm. So GG5's "〔アパート･貸しビルなどの入居者〕 a tenant." is wrong when it mentions "アパート"?
Actually, it probably is. I'll trim it down a bit - it is rather tautological now.

@@ -11,1 +11,1 @@
-<gloss>(commercial) tenant (esp. in an office block or shopping center)</gloss>
+<gloss>tenant (usu. office block, shopping center, etc.)</gloss>

http://ja.wikipedia.org/wiki/テナント

Ok, WP to the rescue – it does state that this is used for *commercial* use.
Specifically, it states (somewhat confusingly): “A tenant is a person who contracts to lease a dwelling to abode therein. But in modern-day Japan it is used exclusively to mean …[various kinds of] (shops).” (i.e., basically it’s a resident, but today it means a commercial tenant).

The specific line is:
「ただし、現代の日本では、。。。事業者（店舗）のこととして専ら用いる。」
Notably 「専ら用いる」 “exclusively used”, AFAICT.

@@ -11,1 +11,1 @@
-<gloss>(commercial) tenant (esp. in an office block)</gloss>
+<gloss>(commercial) tenant (esp. in an office block or shopping center)</gloss>

広辞苑、GG5

Specify *commercial*.
I had vaguely assumed that テナント and 入居者 were synonyms (casual gloss is “tenant” and Japanese friends felt they were different but didn’t clarify much) until I saw a building with:
１Ｆテナント募集
２Ｆ入居者募集
…on it, explicitly contrasting them.
…and then more checking revealed that テナント is esp. commercial (it seems exclusively commercial), while 入居者 is primarily residential, but sometimes commercial.
I’ve tried to reflect this in amended entries.

@@ -11,1 +11,1 @@
-<gloss>tenant</gloss>
+<gloss>(commercial) tenant (esp. in an office block)</gloss>

Adding locked-out xref.

@@ -10,0 +10,1 @@
+<xref type="see" seq="1944870">入居者・にゅうきょしゃ</xref>

Syn

@@ -10,0 +10,2 @@
+<xref type="see" seq="1944870">入居者</xref>
+<xref type="see" seq="1944870">入居者</xref>