Giving particular attention; habitually attentive to what passes; as, an observing person; an observing mind
{i} observance; keeping (of a custom); act of fulfilling (a religious law); watching carefully
using one or more of the senses in perceiving properties or similarities and differences in objects and events; can be made directly with the senses or indirectly through the use of simple or complex instruments; influenced by the previous experience of the observer