The Spanish word 'mediastino' comes from Medieval Latin 'mediastinum', meaning 'that which is in the middle'. This Medieval Latin term was formed by combining two Latin words: 'medius' meaning 'middle' and 'stare' meaning 'to stand'. The word evolved to specifically refer to the anatomical space between the lungs in modern Spanish medical terminology.

Some simpler Spanish words that share the Latin root 'medius' (middle) include 'medio' (middle, half), 'mediano' (medium-sized), and 'mediodía' (noon, midday). These words all retain the core concept of being in the middle or intermediate position, just like how the mediastino is the middle space between the lungs.

The English word 'mediastinum' is directly related to Spanish 'mediastino' as they share the same Medieval Latin origin. Other English words sharing the Latin root 'medius' include 'medium', 'median', 'intermediate', and 'mediator'. From the 'stare' root, we get English words like 'stand', 'stable', 'station', and 'status', all relating to the concept of standing or being positioned.