on the way; en route
Refers to being in the course of moving from one place to another, or during a journey. Often used with verbs of movement or stopping.
I met a friend on the way to school.
On the way home, I stopped by the supermarket.
in the middle of; midway; halfway
Indicates being partway through an action, process, or state, not yet finished. Common with nouns like 仕事, 会議, 食事, or verbs in ている form.
The phone rang in the middle of the meal.
It's still in the middle of construction.
I stopped at a convenience store on the way to the station.
The phone rang in the middle of the meeting.
I stopped doing my homework halfway through.
I changed my mind partway through the trip and decided to go home.
途中 is the common, casual word for 'on the way' or 'midway', while 途上 is more formal and typically appears in set phrases like 発展途上国.
途中 is the everyday word for 'on the way' or 'in the middle of a journey,' while 路上 in that sense is a more literary, travel-imagery way of saying the same thing.
途中 is the everyday word for 'on the way' or 'partway through' an action, while 中途 is more abstract and formal, often describing an incomplete process like leaving school or a job.
途中 is the everyday word for being partway through something or on the way, whereas 中道 conveys the same idea in a more formal or bookish register.
途中 emphasizes being partway through a process or journey, while 中ほど focuses on the physical or sequential middle point itself.
dropping out mid-race; withdrawing during competition; DNF
progress report; interim update; how things are going · in progress; ongoing; underway