The term 'Strength Symbol' can be represented by two crossword solutions: OAK (3 letters) and OAKTREE (7 letters). The OAK tree is a symbol of strength and endurance, and has been used in many cultures throughout history. It is often seen as a symbol of wisdom, stability, and protection. In some cultures, it is also associated with fertility and abundance. The OAK tree is also known for its long life, and is often seen as a symbol of longevity.