Entity matching is a fundamental task in a wide range of retrieval and knowledge applications, aiming to identify whether two objects correspond to the same real-world entity across heterogeneous sources. Typical variants include entity resolution (ER), entity linking (EL), and entity alignment (EA). While recent unified matchers have made progress through multi-task training with comprehensive annotations, real-world pipelines often operate under scarce supervision, where labeled data is incomplete and fails to cover the full spectrum of matching scenarios. In this regime, supervised unified models degrade substantially, and deployable compact LLMs remain unreliable: lightweight fine-tuning and in-context learning yield inconsistent behavior and can even exhibit negative effects under scenario shifts. To fill in this gap, we propose øurs, a meta-rule induction and retrieval framework for unified entity matching under scarce supervision. Instead of relying on parametric adaptation, øurs converts limited supervision into explicit natural-language rules, abstracts them into reusable meta-rules via hierarchical clustering, and retrieves the most relevant meta-rules to guide the LLM's inference for each input instance. This design improves robustness by grounding decisions on explicit and reusable evidence, instead of relying solely on implicit adaptation or prompt demonstrations. Extensive experiments show that øurs achieves state-of-the-art performance on unified entity matching under scarce supervision.