Complicate, a.
Etymology: [L. complicatus, p. p. of complicare to fold together. See Complex.]
1. Composed of two or more parts united; complex; complicated; involved. How poor, how rich, how abject, how august, How complicate, how wonderful is man! Young.
2. (Bot.)
Folded together, or upon itself, with the fold running lengthwise.
1 other Webster entry under this spelling
Complicate, v. t. [imp. & p. p. Complicated; p. pr. & vb. n. Complicating.]
To fold or twist together; to combine intricately; to make complex; to combine or associate so as to make intricate or difficult. Nor can his complicated sinews fail. Young. Avarice and luxury very often become one complicated principle of action. Addison. When the disease is complicated with other diseases. Arbuthnot.
Shades of meaning
Fernald has no entry of its own for complicate; he lists it under involve.
He lists it without comment; the entries above explain its neighbors.