Revolutionary vs. Evolutionary
Business Development, to me, includes all corporate activities to move from evolutionary growth to revolutionary growth.
The difference between evolutionary and revolutionary growth could be, for example, the difference between adding a sales rep, thus adding $1 million in revenue, and adding a new market for an existing product, potentially adding many millions — if executed well, business development then allows to dramatically grow a company with little or no impact on the production departments, be they hardware engineering, software development or manufacturing.