長い
nagai
A long queue, a long friendship — 長い is distance to the end
The picture The place where something starts and the place where it ends, far apart. 長い has the end far away; 短い has the end arriving almost at once.
Where the picture shows up in 長い
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an object's end is far
この袖は少し長いですね。
kono sode wa sukoshi nagai desu ne
This sleeve is a bit long.
A cuff that covers the fingers and hangs down past them
-
time's end is far
今日の会議は長くなりました。
kyō no kaigi wa nagaku narimashita
Today's meeting ran long.
The clock hand sweeping past the hour the meeting was meant to end
長くなる = to run long, to grow longer.
-
a line's end is far
レジの列が長いです。
reji no retsu ga nagai desu
The checkout queue is long.
A queue starting at the register with its tail reaching out the shop door
-
the years stretch far
あの会社とは付き合いが長いです。
ano kaisha to wa tsukiai ga nagai desu
We've dealt with that company for a long time.
A line drawn from the date on the first contract all the way to today's date
付き合いが長い = to have known someone a long time.
-
a speech's end is far
説明が長くなってすみません。
setsumei ga nagaku natte sumimasen
Sorry for the long explanation.
The listener glancing at the clock while the talking still hasn't finished
All of it in one picture
長い is one picture: start and end sitting far apart. The sleeve's end falls past your fingers, so it is long; the meeting's end drifts past the scheduled hour, so it ran long; the tail of the queue reaches out the shop door. From the first contract to today is a long stretch, so the relationship is an old one — and when the end of your explanation is further off than the listener's patience, you apologise for going on too long.