Unlike the everyday use of strength and strength training that is limited to physical aspects, the word strength itself has much broader meanings.
To be strong in the strictest sense includes muscular power, vigor, mental power, moral power and courage, potency, and the ability to resist force.
Many confuse strength training with weight training, resistance training, and muscle training.
To get stronger in lifting weights, you need to increase your ability to lift weights. You can do weight training without progression all your life without getting stronger. You can choose lite weights and do hundreds of reps and call it resistance training without getting stronger.
The word “strength” came from the Old English word, “strengþu,” which translates to “force,” among other things. You are stronger when you can either exert more force or resist it.