blend (something) in

To mix or combine something smoothly or seamlessly with something else. Be sure to blend your makeup in so that your face isn't two different colors. OK, now blend the butter in with the eggs. A: "And if you blend some blue paint in with the red, what color does it make?" B: "Purple!"

blend in(to) (something)

1. To combine one or more ingredients uniformly into another substance or a larger mixture. In this usage, a noun or pronoun can be used between "blend" and "in," and it is always used between "blend" and "into." Next, blend the butter in with the rest of the ingredients. Start blending the flour into the soup stock to help thicken it. Be sure to blend in your makeup so that your face isn't two different colors.

2. To merge seamlessly and successfully with some thing or a group of people. Do you think Sam will be able to blend into the group? He can be pretty standoffish. Don't wear anything too flashy—try to blend into the background. I recognized the famous actress, but I didn't say anything because she was clearly just trying to blend into the crowd at the mall.

blend in (to something)

to combine nicely with something; to mix well with something. The oil won't blend into the water very well. It simply won't blend in.