One ear refers to the condition of having only one functioning ear, either due to a congenital defect or as a result of injury or illness. This term can also be used to describe someone who is only able to hear out of one ear, often resulting in difficulties with sound localization and understanding speech in noisy environments. In a broader sense, ‘one ear’ can also be used to describe someone who is selectively listening or paying attention to only one side of a conversation or situation. This term can also be used figuratively to describe someone who is not fully open to hearing different perspectives or ideas.