There is wide agreement within a particular culture on what common physical objects are. When you say "car" or "refrigerator" most people will have an understanding very close to yours. When using words for abstract qualities, like "trust", "love", "right", or "wrong", there is wide variance in meaning. For effective communication one must consider all the factors involved; different realities, the space where communication occurs, verbal as well as non-verbal messages and the intended meaning versus the perceived meaning.