Silver, Yang and Li define lifelong machine learning in [1] as: "Lifelong Machine Learning, or LML, considers systems that can learn many tasks over a lifetime from one or more domains. They efficiently and effectively retain the knowledge they have learned and use that knowledge to more efficiently and effectively learn new tasks."
Taylor, Kuhlmann and Stone name the requirements for a transfer learning algorithm in [2]: "1. Select an appropriate source task from which to transfer, given a target task. 2. Learn how the source task and target task are related. 3. Effectively transfer knowledge from the source task to the target task."
Aren't those pretty similar definitions?
[1] https://www.researchgate.net/publication/242025320_Lifelong_Machine_Learning_Systems_Beyond_Learning_Algorithms
[2] https://www.researchgate.net/publication/200502413_Autonomous_transfer_for_reinforcement_learning
Conference Paper Lifelong Machine Learning Systems: Beyond Learning Algorithms
Conference Paper Autonomous transfer for reinforcement learning