Lavender (#E6E6FA) is a very light, moderately saturated blue hue. The CSS lavender keyword is a very pale bluish purple; real lavender flowers are deeper.
In RGB it is made of 230 red, 230 green and 250 blue. Its HSL hue angle is 240° with 67% saturation and 94% lightness, while its perceptual OKLCH lightness is 93% with a chroma of 0.027. For print, a starting CMYK mix is 8% cyan, 8% magenta, 0% yellow and 2% black.
As a text color on white, Lavender has a contrast ratio of 1.23:1, which fails WCAG AA even for large text. On black it reaches 17.06:1 and passes AA for normal text. If you use Lavender as a background, put black (or very dark) text on it. The APCA lightness contrast is Lc 92 for black text and Lc -13 for white text.
Its perceptual complement is #EAEAD5, close to champagne. Colors that look most similar are off-white, champagne, beige. It looks fairly similar to people with red-green color blindness (ΔE 1), so its meaning mostly survives.