| A | B |
| hyperactive | very restless |
| hypothesis | a theory that is unproven but used under the assumption that it is true |
| pediatrician | a doctor who treats children |
| icon | an (often religious) image |
| idiot | someone who is distinctly foolish or stupid |
| illuminate | to give light to |
| image | a likeness of someone |
| infrastructure | underlying framework of a system |
| intersection | place where roads come together |
| introvert | shy person who keeps within him/herself |