HARD/FIRM›hard and firm without holes or spaces, and not liquid or gas: solid groundsolid food
STRONG›strong and not easily broken or damaged: solid furniture
solid gold/silver/wood, etc›gold/silver/wood, etc with nothing added: a solid silver bracelet
TIME›continuing for a period of time without stopping: The noise continued for two solid hours/two hours solid.
INFORMATION[always before noun]›Solid information, proof, etc is based on facts and you are certain that it is correct: This provides solid evidence that he committed the crime.