a single thing that is taken as an example of a whole category
specimen
1. a ghost
2. a haunting fear of future trouble
specter
1. the distribution of characteristics of a physical system, especially bands of colors seen as a rainbow or bands of differing sound waves
2. a wide range of related qualities or ideas
spectrum
1. to form opinions without definite knowledge or evidence
2. to buy or sell something to make a profit but with risk of loss
speculate
supervision or close observation, especially of a suspected person