A houseplant is any kind of decorative plant. People grow them indoors, sometimes in a house, but very often in an office or a shop.
Houses or public premises have conditions not as favorable for plants as in greenhouses. For example, the direction of light, low light, dry air, dust, drafts, uneven temperature. So, special techniques are used to get a healthy state and proper development of plants. Conditions in public and office premises are usually even less favorable than in homes, so the most hardy indoor plants are grown there.