hand_in_hand
1. [ adverb ] together
Examples:

"hand in hand with hope went fear" "doctors and nurses work hand in hand to save lives"

2. [ adverb ] clasping each other's hands
Examples:

"they walked hand in hand"

Similar spelling:   hand_to_hand
  hand_and_foot
  hand_and_glove
  hand_in_glove
  hand_down
  hand-to-hand