what is the difference between signal and wave

A signal is an abstract concept, it is only information and has no physical manifestation.

A wave is a physical phenomenon, and can be measured in a lab or simulated.

Waves can be used to transmit signals. For example, an electromagnetic wave can be modulated in amplitude to carry an AM signal. This AM-modulated wave is still just a wave. The signal it carries is the interpretation of the wave by a radio receiver. Other types of receivers, for example an FM receiver, will interpret the same wave as carrying no signal.

thank you for ur reply...what is the difference between sinusoidal wave and sinusoidal signal (please forgive my foolishness)

Lack of knowledge perhaps, not foolishness.

Take for example a sinusoidal voltage wave. If we interpret the voltage in the time-domain as the signal, we'd have a sinusoidally varying signal. If we interpret the voltage in the frequency domain as the signal, we'd have a constant valued signal. The wave is the same in both cases, but the signal (the interpretation of the wave) is different.

Many people will use the terms interchangeably -- this is strictly incorrect, but common nonetheless.

'Signal' is a flexible word. It can mean anything of interest. It can mean the quality of sinewave. "I'm getting no signal. I'm getting a bad signal. I'm getting a good signal." Etc.

Signal can mean information which is sent through the sinewave (see post #2).
Example, by varying amplitude, or frequency, or simple On-Off fashion.