semantic structure of the noun fire could be roughly presented by this scheme (only the most frequent meanings are given):
An instance of destructive burning; e. g. a forest fire.
Burning material in a stove, fireplace, etc.; e. g. There is a fire in the next room. A camp fire.
The shooting of guns, etc.; e. g. to open (cease) fire.
Strong feeling, passion, enthusiasm; e. g. a speech lacking fire.
The above scheme suggests that meaning I holds a kind of dominance over the other meanings conveying the concept in the most general way whereas meanings II—V are associated with special circumstances, aspects and instances of the same phenomenon.
Meaning I (generally referred to as the main meaning) presents the centre of the semantic structure of the word holding it together. It is mainly through meaning I that meanings II—V (they are called secondary meanings) can be associated with one another, some of them exclusively through meaning I, as, for instance, meanings IV and V.
It would hardly be possible to establish any logical associations between some of the meanings of the noun bar except through the main meaning:1
1 We give only a fragment of the semantic structure of bar, so as to illustrate the point.