also from the previous link:
"The admitted-until date or D/S notation, shown on your admission stamp or paper Form I-94 is the official record of your authorized 
length of stay in the United States. You cannot use the visa expiration date in determining or referring to your permitted length of stay 
in the United States."

@@ -13 +13 @@
-<gloss>validity period (of a visa)</gloss>
+<gloss>authorized length of stay</gloss>

(also in the US, apparently: https://travel.state.gov/content/travel/en/us-visas/visa-information-resources/visa-expiration-date.html
"Admission to the United States and your Duration of Stay
Upon arriving at a port of entry, the CBP official will determine the length of your visit.

On the admission stamp or paper Form I-94, the U.S. immigration inspector records either an admitted-until date or "D/S" (duration of 
status). If your admission stamp or paper Form I-94 contains a specific date, then that is the date by which you must leave the United 
States. ")

@@ -12,0 +13 @@
+<gloss>validity period (of a visa)</gloss>

"duration of stay" is the Schengen area phrase 
for this.

@@ -12,0 +13 @@
+<gloss>duration of stay</gloss>

gg5
daijs: 在留資格を持つ外国人が日本に在留できる期間。在留資格によって異なる。入管法・同施行規則に規定。

I think we need to make it more specific.

@@ -12,2 +12 @@
-<gloss>period of stay</gloss>
-<gloss>duration of stay</gloss>
+<gloss>(permitted) period of stay (in a country)</gloss>