Engulfing

Engulfing is a term used to describe the act of surrounding, enclosing, or completely covering something by another substance or object. In everyday use it can refer to physical processes such as a fire engulfing a building or floodwaters engulfing an area, as well as to biological or financial concepts where one entity completely surrounds another.

In biology, engulfment is a form of endocytosis known as phagocytosis. In phagocytosis, cells such as macrophages and neutrophils recognize and surround foreign particles, pathogens, or debris, deforming their cell membrane to enclose the target within a vesicle called a phagosome. The phagosome then fuses with lysosomes, where enzymes digest the contents. Receptors on the cell surface and opsonins can enhance recognition and uptake.

In finance and technical analysis, engulfing refers to a candlestick pattern that signals a potential reversal. A bullish engulfing pattern occurs when a small bearish candle is followed by a larger bullish candle whose body completely covers or engulfs the previous day's body. A bearish engulfing pattern is the opposite: a larger bearish candle engulfs a smaller bullish candle. The pattern is most meaningful when accompanied by appropriate volume and occurs after a price movement that suggests exhaustion of the current trend.

Other uses are descriptive and metaphorical, such as an audience engulfed by a performance or a region engulfed by drought. The term emphasizes a total or near-total surrounding effect rather than partial coverage.