BOSTON (AP) _ Affiliated Publications Inc., parent company of The Boston Globe, said it has reached an agreement to acquire Billboard Publications Inc. for $100 million in cash.

The New-York based Billboard publishes eight specialty magazines and many books for the arts, music and entertainment markets, including Billboard Magazine, a weekly publication about the entertainment industry.

Under the agreement announced Friday, Affiliated will acquire Billboard from a shareholder group led by Boston Ventures Limited Partnership.

''This purchase gives Affiliated's profile a new dimension,'' said William O. Taylor, Affiliated board chairman and chief executive officer. ''It give us, in one stroke, a strong position in the growing business of specialty magazines.''

Under a separate agreement, some Billboard managers plan to purchase up to 10 percent of the equity in Billboard Publications following the acquisition.

''In addition to acquiring a successful company, it also assures us of excellent management in the magazine industry for future expansion,'' said John P. Giuggio, Affiliated president.

Billboard publishes 15 annual directories, distributes specialty books under four imprints, operates two book clubs and hosts several annual industry conferences.

Affiliated is the parent company of Globe Newspaper Co., publisher of the Globe; owns Globe Pequot Press Inc, a small book publisher; and owns 45 percent of McCaw Communications Companies, Inc., of Kirkland, Wash., which has interests in cellular telephone and paging systems.