It literally means "serious accounts" but the specific meaning will depend on the context. Here are some possible interpretations:
* Financial Accounts: This could refer to financial records that are of significant importance or concern.
* Historical Accounts: This could refer to historical records that are considered serious or significant.
* Personal Accounts: This could refer to personal experiences or stories that are considered serious or impactful.
To understand the precise meaning, you'd need more context about where you encountered this phrase.