The meaning of instrumental music is in my opinion deeply connected to the perception of life in general. For many different people usually have very similar feelings about an instrumental piece, the music seems to be deeply related to something like the collective unconcious.
Instrumental music - if well written - expresses always common perceptions of life, or "draws" well known pictures of nature, and therefore is kind of a holistic form of communication, or better transportation, of feelings, experiences or parts of the 'conditio humana'.
It carries holistic information on a non-verbal level, and therefore can (usually) be immediately understood deeply inside of us, without the need for interpretation or translation, and without the commonly known misunderstandings of verbal communication. It affects the innermost, more intuitiv and archaic parts of our brains, and has therefore a very powerful and direct effect.
This is also the reason for the use of instrumental music in movie productions. To give an example, see Stanley Kubrick's "2001 - a space odyssey", where the impact of non-verbal music (or the absence of it) is one of the most important creative means and has a thrilling, direct effect on almost every viewer.
Or see Gustav Mahler's 6th symphony (especially the last movement), where most of the audience understand the big picture of struggle and devastation without having read their booklet.
Or - to give perhaps more commonly known examples - see the program music of the 19th century with pieces like Beethoven's 6th symphony or Smetana's 'Ma vlast - My homeland' with its part 'Vltava - The Moldau'.
Perhaps there is - besides the above mentioned effects - also kind of a common traditional consensus about the meaning of certain forms of non-verbal music, to be experienced for example in the peasant's wedding dance of 'The Moldau'. We all know such feasts and the music being played at them. But this is - in my opinion - a by far less important aspect than the former mentioned.