You are working on a crossword puzzle. Even though you know the answer to a question, you cannot remember the actual word. You remember the shape of the word, the first letter of the word, and other related words and ideas, but you cannot remember the word itself. You are experiencing

You are experiencing the tip-of-the-tongue phenomenon.

Explanation:

The tip-of-the-tongue phenomenon is also known as lethologica. It can be defined as the feeling we have when we are temporarily unable to retrieve information from memory. It is interesting to note that partial information can be recalled. If we are trying to remember a particular word, we may recall its first letter, or how many syllables we have, for instance. This phenomenon is common and becomes more frequent as we age.