Синий
Покой, дистанция и прохладная часть спектра — то, что держится ровно.
Blue in a dream is the dictionary's image of the calm, cool part of the spectrum. Blue water, blue sky, a blue object — the dream uses the colour to signal steadiness, often after a stretch of more turbulent imagery.
Where you often see it. A blue sky after rain. Blue water in a quiet lake. A blue piece of clothing on someone you usually see in warmer colours. The dream uses blue to mark the moment a situation cools and becomes stable enough to read.
What it is not. Blue is not sadness in the dictionary's house style. Cultural shorthand reads blue as low mood; the dream reads it as steadied attention.
Related in the dictionary. Pair blue with water (emotion held in a known shape), sky (overview), and white (clarity). Compare against red (intensity) when both colours appear in one dream.