Secondary
Overview
'Secondary' generally means 'second' or 'secondary,' representing important turning points or stages in diverse fields including history, society, science, and technology. Notably, World War II, the Second Industrial Revolution, secondary sexual characteristics, and secondary infections are core concepts in their respective domains. This article comprehensively examines the main contexts and meanings in which 'secondary' is used.
Main Content
Secondary in Historical Context
World War II (1939-1945)
World War II was the most widespread and destructive war in human history, beginning with Germany's invasion of Poland in 1939 and ending with Japan's surrender in 1945. This war involved a confrontation between the Allied Powers (the United States, the United Kingdom, the Soviet Union, China, etc.) and the Axis Powers (Germany, Italy, Japan), with over 30 countries participating. Major battles included the Normandy landings, the Battle of Stalingrad, and the Battle of Midway, and the use of atomic bombs impressed upon humanity the power of nuclear weapons. World War II shaped the foundations of the modern world order, including the establishment of the United Nations (UN), the beginning of the Cold War, and decolonization.
Second Industrial Revolution (late 19th to early 20th century)
The Second Industrial Revolution was a wave of technological innovation that unfolded from the late 19th to the early 20th century, following the First Industrial Revolution. The emergence of new energy sources and materials such as electricity, chemicals, steel, and oil established mass production systems, and inventions like the telephone, light bulb, and internal combustion engine transformed daily life. In particular, Henry Ford's introduction of the assembly line dramatically improved productivity, and this period spurred the full-scale development of capitalism and the growth of labor movements.
Secondary in Science and Medicine
Secondary Sexual Characteristics
Secondary sexual characteristics are features of sexual dimorphism that appear during puberty, making physical differences between males and females more pronounced. In males, these include facial hair, voice changes, and muscle development; in females, they include breast development, pelvic widening, and the onset of menstruation. These are triggered by hormonal changes and significantly influence individual identity formation and social roles.
Secondary Infection
A secondary infection refers to an additional infection that occurs in the presence of an existing disease or immunocompromised state. For example, pneumonia following influenza or opportunistic infections due to HIV infection are cases of secondary infection. Secondary infections can complicate treatment of the original disease and increase mortality, making prevention and early detection important.
Secondary in Social and Cultural Context
Second-Wave Feminism (1960s-1980s)
Second-wave feminism expanded the women's movement beyond first-wave feminism (focused on suffrage) into broader areas such as gender equality, reproductive rights, and division of roles within the home. Works like Betty Friedan's 'The Feminine Mystique' had a significant impact, and the movement unfolded alongside the civil rights movement in the United States during the 1960s. Key issues during this period included legalization of abortion, equal pay, and the eradication of sexual violence.
Second Wave of Globalization (post-1990s)
The second wave of globalization refers to the accelerated global integration following the end of the Cold War, driven by free trade and advances in information and communication technology. While the first wave of globalization (late 19th century to 1914) was based on colonial expansion, steamships, and railways, the second wave is characterized by the internet, container shipping, and the spread of multinational corporations. This period saw a sharp increase in global economic interdependence, but the 2008 financial crisis and the COVID-19 pandemic in 2020 prompted discussions of deglobalization.
Secondary in Technology and Economy
Secondary Battery (Rechargeable Battery)
A secondary battery is a rechargeable battery, unlike a primary battery (single-use), and can be reused. Representative types include lithium-ion batteries and nickel-metal hydride batteries, which have become core components of modern technology such as smartphones, electric vehicles, and energy storage systems (ESS). Recently, with the growth of the electric vehicle market, innovation in battery technology has accelerated, and next-generation technologies such as solid-state batteries are gaining attention.
Secondary Market (Secondhand Market)
The secondary market is a market where used products are traded, including used cars, used electronics, and used clothing. Recently, due to the spread of environmental awareness and the pursuit of economic efficiency, the secondary market has grown rapidly. In particular, the development of the platform economy has facilitated secondhand transactions, and it is recognized as a key element of the 'circular economy.'
Latest Trends
As of 2024-2025, major trends related to 'secondary' include:
- Innovation in Secondary Battery Technology: Despite the slowdown in the electric vehicle market, development of low-cost, high-safety batteries such as lithium iron phosphate (LFP) batteries and sodium-ion batteries is active. Additionally, as battery recycling technology becomes important, the 'second-life' battery market is expanding.
- Reexamination of World War II: 2025 marks the 80th anniversary of the end of World War II, with commemorative events and historical reassessments underway in various countries. In particular, differences in historical perception among Japan, South Korea, and China remain contentious.
- Legacy of Second-Wave Feminism and Fourth-Wave Feminism: Building on the achievements of second-wave feminism, fourth-wave feminism (including the #MeToo movement) has been unfolding in the digital environment since the 2010s. In 2024, the issue of 'secondary victimization' (2차 가해) emerged as a social issue in South Korea, sparking active discussions on victim protection and perpetrator punishment.
- Prevention of Secondary Infections: Following the COVID-19 pandemic, research and vaccine development for secondary infections (especially in immunocompromised individuals) have been strengthened. In 2024, the RSV (respiratory syncytial virus) vaccine was introduced for the elderly, expanding the scope of vaccination.
Related Topics
- [[Primary]]
- [[World War]]
- [[Industrial Revolution]]
- [[Feminism]]
- [[Battery]]
- [[Secondhand Market]]
- [[Sexual Characteristics]]
- [[Infection]]
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