BOS and CHoCH

The market never moves in a straight line. It moves in waves.
It makes a High, comes down a bit (Low), then breaks the previous High to make a new High.
Similarly, It makes a Low, goes up a bit (High), then breaks the previous Low to make a new Low.

BOS (Break Of Structure) - Trend Continuation
BOS means the market is continuing its current trend. If the market is in an Uptrend and breaks the old "High" -> Bullish BOS. If the market is in a Downtrend and breaks the old "Low" -> Bearish BOS.

3. CHOCH (Change Of Character) - Trend Reversal
CHOCH means the mood of the market has changed. For the first time, the trend has shifted its nature.

Bullish to Bearish CHOCH: The market was making Higher Highs, but suddenly it broke its previous "Low". Now the market can fall.

Bearish to Bullish CHOCH: The market was falling (Lower Lows), but suddenly it broke its previous "High". Now the market can rise.

BOS: Confirms the trend (Breaking the ceiling to go higher).
CHOCH: Signals a trend change (Slipping and falling below the previous floor).